Press Contact: Kelsey Davenport, Director for Nonproliferation Policy, (202) 463-8270 x102
Iran has been engaged in efforts to acquire the capability to build nuclear weapons for more than two decades. Although it remains uncertain whether Tehran will make the final decision to build nuclear weapons, it has developed a range of technologies, including uranium enrichment, warhead design, and delivery systems, that would give it this option in a relatively short time frame. Tehran maintains that its nuclear activities are entirely peaceful. Various states have made efforts over the years to negotiate a settlement with Iran that limits its nuclear program.
What follows is a chronological recount of the most significant developments in Iran’s nuclear program and international efforts to negotiate a settlement to address this controversial issue.
November 1967: Iran’s first nuclear reactor, the U.S. supplied five-megawatt Tehran Research Reactor (TRR) goes critical. It operates on uranium enriched to about 93 percent (it is converted to run on 20 percent in 1993,) which the United States also supplies.
February 1970: The Iranian parliament ratifies the nuclear Nonproliferation Treaty (NPT).
1974: Shah Reza Pahlavi establishes the Atomic Energy Organization of Iran (AEOI) and announces plans to generate about 23,000 megawatts of energy over 20 years, including the construction of 23 nuclear power plants and the development of a full nuclear fuel cycle.
1979: The Iranian Revolution and the seizure of the U.S. embassy in Tehran result in a severing of U.S.-Iranian ties and damages Iran’s relationship with the West. Iranian nuclear projects are halted.
January 19, 1984: The U.S. Department of State adds Iran to its list of state sponsors of terrorism, effectively imposing sweeping sanctions on Tehran.
1987: Iran acquires technical schematics for building a P-1 centrifuge from the Abdul Qadeer Khan network.
1992: Congress passes the Iran-Iraq Arms Nonproliferation Act of 1992, which prohibits the transfer of controlled goods or technology that might contribute “knowingly and materially” to Iran’s proliferation of advanced conventional weapons.
1993: Conversion of the TRR is completed by Argentina’s Applied Research Institute. It now runs on fuel enriched to just less than 20 percent, 115 kilograms of which is provided by Argentina; the contract for the conversion was signed in 1987.
August 5, 1996: The U.S. Congress passes the Iran-Libya Sanctions Act, also known as the Iran Sanctions Act, that penalizes foreign and U.S. investment exceeding $20 million in Iran’s energy sector in one year.
August 2002: The National Council of Resistance on Iran, the political wing of the terrorist organization Mujahideen-e Khalq (MeK), holds a press conference and declares Iran has built nuclear facilities near Natanz and Arak.
September 12, 2003: The International Atomic Energy Agency (IAEA) Board of Governors adopts a resolution calling for Iran to suspend all enrichment – and reprocessing- related activities. The resolution requires Iran to declare all material relevant to its uranium-enrichment program and allow IAEA inspectors to conduct environmental sampling at any location. The resolution requires Iran to meet its conditions by October 31st 2003.
October 21, 2003: Iran agrees to meet IAEA demands by the October 31st deadline. In a deal struck between Iran and European foreign ministers, Iran agrees to suspend its uranium–enrichment activities and ratify an additional protocol requiring Iran to provide an expanded declaration of its nuclear activities and granting the IAEA broader rights of access to sites in the country.
June 18, 2004: The IAEA rebukes Iran for failing to cooperate with IAEA inspectors. Iran responds by refusing to suspend enrichment-related activities as it had previously pledged.
November 14, 2004: Iran notifies the IAEA that it will suspend enrichment-related activities following talks with France, Germany, and the United Kingdom. According to the so-called Paris Agreement, Iran would maintain the suspension for the duration of talks among the four countries. As a result, the IAEA Board of Governors decides not to refer Tehran to the UN Security Council.
February 27, 2005: Russia and Iran conclude a nuclear fuel supply agreement in which Russia would provide fuel for the Bushehr reactor it is constructing and Iran would return the spent nuclear fuel to Russia. The arrangement is aimed at preventing Iran from extracting plutonium for nuclear weapons from the spent nuclear fuel.
August 8, 2005: Iran begins producing uranium hexafluoride at its Isfahan facility. As a result, France, Germany, and the United Kingdom halt negotiations with Tehran.
September 24, 2005: The IAEA adopts a resolution finding Iran in noncompliance with its safeguards agreement by a vote of 22-1 with 12 members abstaining. The resolution says that the nature of Iran’s nuclear activities and the lack of assurance in their peaceful nature fall under the purview of the UN Security Council, paving the way for a future referral.
February 4, 2006: A special meeting of the IAEA Board of Governors refers Iran to the UN Security Council. The resolution “deems it necessary for Iran to” suspend its enrichment-related activities, reconsider the construction of the Arak heavy-water reactor, ratify the additional protocol to its safeguards agreement, and fully cooperate with the agency’s investigation.
February 6, 2006: Iran tells the IAEA that it will stop voluntarily implementing the additional protocol and other non-legally binding inspection procedures.
April 11, 2006: Iran announces that it has enriched uranium for the first time. The uranium enriched to about 3.5 percent was produced at the Natanz pilot enrichment plant.
June 6, 2006: China, France, Germany, Russia the United Kingdom, and the United Sates (the P5+1, referring to the five permanent members of the UN Security Council and Germany) propose a framework agreement to Iran offering incentives for Iran to halt its enrichment program for an indefinite period of time.
July 31, 2006: The UN Security Council adopts Resolution 1696, making the IAEA’s calls for Iran to suspend enrichment –related and reprocessing activities legally binding for the first time.
August 22, 2006: Iran delivers a response to the P5+1 proposal, rejecting the requirement to suspend enrichment but declaring that the package contained “elements which may be useful for a constructive approach.”
December 23, 2006: The UN Security Council unanimously adopts Resolution 1737, imposing sanctions on Iran for its failure to suspend its enrichment-related activities. The sanctions prohibit countries from transferring sensitive nuclear- and missile-related technology to Iran and require that all countries freeze the assets of ten Iranian organizations and twelve individuals for their involvement in Iran’s nuclear and missile programs.
March 24, 2007: The UN Security Council unanimously adopts Resolution 1747 in response to Iran’s continued failure to comply with the council’s demand to suspend Uranium enrichment.
August 21, 2007: Following three rounds of talks in July and August, the IAEA and Iran agree on a “work plan” for Iran to answer long-standing questions about its nuclear activities, including work suspected of being related to nuclear weapons development.
December 3, 2007: The United States publicly releases an unclassified summary of a new National Intelligence Estimate report on Iran’s nuclear program. The NIE says that the intelligence community judged “with high confidence” that Iran halted its nuclear weapons program in the fall of 2003 and assessed with moderate confidence that the program had not resumed as of mid-2007. The report defines Iran’s nuclear weapons program as “design and weaponization work” as well as clandestine uranium conversion and enrichment. The NIE also said that Iran was believed to be technically capable of producing enough highly enriched uranium for a nuclear weapon between 2010 and 2015.
March 3, 2008: The UN Security Council passes Resolution 1803, further broadening sanctions on Iran. It requires increased efforts on the part of member states to prevent Iran from acquiring sensitive nuclear or missile technology and adds 13 persons and seven entities to the UN blacklist.
June 14, 2008: The P5+1 present a new comprehensive proposal to Iran updating its 2006 incentives package. The new proposal maintained the same basic framework as the one in 2006, but highlighted an initial “freeze-for-freeze” process wherein Iran would halt any expansion of its enrichment activities while the UN Security Council agreed not to impose additional sanctions.
February 3, 2009: Iran announces that it successfully carried out its first satellite launch, raising international concerns that Iran’s ballistic missile potential was growing.
April 8, 2009: Following an Iran policy review by the new Obama administration, the United States announces that it would participate fully in the P5+1 talks with Iran, a departure from the previous administration’s policy requiring Iran to meet UN demands first.
June 12, 2009: Iran holds presidential elections. Incumbent Mahmoud Ahmadinejad is declared the winner amid many indications that the election was rigged. This sparks weeks of protests within Iran and delays diplomatic efforts to address Iran’s nuclear program.
September 25, 2009: United States President Barack Obama, British Prime Minister Gordon Brown, and French President Nicolas Sarkozy announced that Iran has been constructing a secret, second uranium-enrichment facility, Fordow, in the mountains near the holy city of Qom. IAEA spokesman Marc Vidricaire said that Iran informed the agency September 21 about the existence of the facility, but U.S. intelligence officials said Iran offered the confirmation only after learning that it had been discovered by the United States.
October 1, 2009: The P5+1 and Iran agree “in principle” to a U.S.-initiated, IAEA-backed, proposal to fuel the TRR. The proposal entails Iran exporting the majority of its 3.5 percent enriched Uranium in return for 20 percent-enriched uranium fuel for the TRR, which has exhausted much of its supply. This agreement was later met with domestic political opposition in Iran, resulting in attempts by Tehran to change the terms of the “fuel swap.”
February 9, 2010: Iran begins the process of producing 20 percent enriched uranium, allegedly for the TRR.
May 17, 2010: Brazil, Iran, and Turkey issue a joint declaration attempting to resuscitate the TRR fuel-swap proposal. In the declaration, Iran agrees to ship 1,200 kilograms of 3.5 percent enriched uranium to Turkey in return for TRR fuel from France and Russia. France, Russia, and the United States reject the arrangement, citing Iran’s larger stockpile of 3.5 percent-enriched uranium and the failure of the declaration to address Iran’s enrichment to 20 percent.
June 9, 2010: The UN Security Council adopts Resolution 1929, significantly expanding sanctions against Iran. In addition to tightening proliferation-related sanctions and banning Iran from carrying out nuclear-capable ballistic missile tests, the resolution imposes an arms embargo on the transfer of major weapons systems to Iran.
June 24, 2010: Congress adopts the Comprehensive Iran Sanctions, Accountability, and Divestment Act; tightening U.S. sanctions against firms investing in Iran’s energy sector, extending those sanctions until 2016, and imposing new sanctions on companies that sell refined petroleum to Iran.
July 26, 2010: The EU agrees to further sanctions against Iran. A statement issued by EU member state foreign ministers refers to the new sanctions as “a comprehensive and robust package of measures in the areas of trade, financial services, energy, [and] transport, as well as additional designations for [a] visa ban and asset freeze.
September 16, 2010: The Stuxnet computer virus is first identified by a security expert as a directed attack against an Iranian nuclear-related facility, likely to be the Natanz enrichment plant.
January 21-22, 2011: Following a December meeting in Geneva, the P5+1 meets with Iran in Istanbul, but the two sides do not arrive at any substantive agreement. Iran’s two preconditions for further discussions on a fuel-swap plan and transparency measures, recognition of a right to enrichment and the lifting of sanctions, were rejected by the P5+1.
February 16, 2011: U.S. intelligence officials tell a Senate committee that Iran has not yet decided whether it wants to develop nuclear weapons but is keeping that option open through development of its material capabilities.
May 8, 2011: Iran’s Bushehr nuclear power plant begins operations and successfully achieves a sustained chain reaction two days later, according to Atomstroyexport, the Russian state-owned company constructing and operating the plant.
June 8, 2011: Iran announces that it intends to triple the rate of 20 percent-enriched uranium production using more-advanced centrifuge designs. It also says it will move production to the Fordow enrichment plant near Qom, which is still under construction.
July 12, 2011: Russian foreign minister Sergey Lavrov unveils a proposal wherein Iran would take steps to increase cooperation with the IAEA and carry out confidence-building measures in return for a gradual easing of sanctions.
October 21, 2011: EU foreign policy chief, Catherine Ashton, sends a letter to Iranian nuclear negotiator Saeed Jalili calling for “meaningful discussions on concrete confidence-building steps” to address international concerns about Iran’s nuclear ambitions.
November 8, 2011: The IAEA releases a report detailing a range of activities related to nuclear weapons development in which Iran is suspected to have engaged as part of a structured program prior to 2004. The report raises concerns that some weapons-related activities occurred after 2003. The information in the report is based primarily on information received from other countries, but also includes information from the agency’s own investigation. The findings appear consistent with the U.S. 2007 National Intelligence Estimate on Iran.
December 31, 2011: As part of the fiscal year 2012 National Defense Authorization Act, Congress passes legislation that will allow the United States to sanction foreign banks if they continue to process transactions with the Central Bank of Iran.
January 2012: The EU passes a decision that will ban all member countries from importing Iranian oil beginning July 1, 2012. Other provisions of the decision will prevent member countries from providing the necessary protection and indemnity insurance for tankers carrying Iranian oil.
January 29-31, 2012: Following an exchange of letters between Iran and the IAEA, it was agreed that an Agency team would travel to Tehran to begin discussions on the IAEA’s investigations into the possible military dimensions of Iran’s nuclear program laid out in the November 2011 IAEA report.
February 15, 2012: Jalili responds to Ashton’s Oct. 21 letter, while Iran simultaneously announces a number of nuclear advances, including the domestic production of a fuel plate for the TRR.
April 14, 2012: Iran meets with the P5+1 in Istanbul for talks both sides call “positive.” They agree on a framework of continuing negotiations with a step-by-step process and reciprocal actions.
May 23-24, 2012: Iran and the P5+1 meet in Baghdad for a second set of talks.
June 18-19, 2012: Talks between Iran and the P5+1 continue in Moscow. Representatives discuss the substance of a P5+1 proposal and an Iranian proposal. Ashton and Jalili announce that will determine if political-level talks will continue after a technical-level meeting in July.
July 3, 2012: Experts representing the six parties meet in Istanbul to discuss the technical aspects of the P5+1 proposal and the Iranian proposal.
July 24, 2012: Schmid and Bagheri meet in Istanbul to discuss the outcome of the technical level experts meeting and confirm that Ashton and Jalili will talk to determine the future of the negotiations.
August 30, 2012: The IAEA reports that Iran increased the number of centrifuges installed at the Fordow enrichment plant and is continuing to produce uranium enriched to 20 percent in excess of its needs for the Tehran Research Reactor.
September 2012: Ashton and Jalili meet in Istanbul to assess “common points” reached at the low-level expert talks held in early July. The meeting was not considered a formal negotiation.
September 27, 2012: In a speech to the UN General Assembly, Israeli Prime Minister Benjamin Netanyahu draws a red-line for an Israeli attack on Iran. Netanyahu defines his red-line as Iran amassing enough uranium enriched to 20 percent (approximately 250 kilograms), which, when further enriched, will be enough for one bomb.
November 16, 2012: The IAEA reports that since August, Iran completed installation of the approximately 2,800 centrifuges that Fordow is designed to hold, although the number enriching remains constant. The number of cascades producing 20 percent enriched uranium remains constant at Fordow. The report also notes that Iran installed more centrifuges at Natanz,, and continued producing uranium enriched to 20 percent.
February 26, 2013: Iran and the P5+1 resume negotiations in Almaty, Kazakhstan over Iran's nuclear program. The P5+1 offers Iran an updated proposal based largely on the 2012 package.
April 5-6, 2013: Iran and the P5+1 meet again in Almaty for a second round of talks. At the end of the meetings, negotiators announce that no further meetings are scheduled and the sides remain far apart.
June 3, 2013: At the quarterly meeting of the IAEA Board of Governors, Director General Yukiya Amano says that the agency's talks with Iran over clarifying the possible military dimensions of Iran's nuclear program have not made any progress.
June 14, 2013: Hassan Rouhani is elected president of Iran. A former nuclear negotiator, he asserts that Iran will maintain its nuclear program, but offers to be more transparent.
August 6, 2013: Three days after his inaguration, Iran's President Hasan Rouhani calls for the resumption of serious negotiations with the P5+1 on Iran's nuclear program.
September 26, 2013: The P5+1 foreign ministers meet with Iranian Foreign Minister Javad Zarif on the sidelines on the UN General Assembly meeting in New York. Zarif presents the P5+1 with a new proposal that U.S. Secretary of State John Kerry describes as “very different in the vision” of possibilities for the future. Zarif and Kerry meeting for a bilateral exchange after the larger group meeting. Zarif later says he and Kerry move to agree “first, on the parameters of the end game.” Zarif says Iran and the P5+1 will think about the order of steps that need to be implemented to “address the immediate concerns of [the] two sides” and move toward finalizing a deal within a year. The parties agree to meet again on October 15 in Geneva.
September 27, 2013: President Barack Obama calls Iranian President Hassan Rouhani, marking the highest level contact between the U.S. and Iran since 1979. While President Obama says that there will be significant obstacles to overcome, he believes a comprehensive resolution can be reached.
In Vienna, Iran's new envoy to the IAEA, Reza Najafi, meets with IAEA deputy director Herman Nackaerts to resume negotitations on the structured approach to resolving the agency's concerns about the possible military dimensions of Iran's nuclear program. Both sides describe the meeting as constructive and agree to meet again on October 28.
October 15-16, 2013: Iran and the P5+1 meet in Geneva to resume negotiations over Iran's nuclear program. At the end of the talks, the parties release a joint statement describing the meetings as "substantive and forward looking." The statement also says that Iran presented a new proposal that the P5+1 carefully considered as an "important contribution" to the talks. The proposal is understood to contain a broad framework for a comprehensive agreement and an interim confidence building measure to be instituted over the next 3-6 months, but no details are given as the parties agreed to keep the negotiations confidential.
Wendy Sherman, Undersecretary of State for Political Affairs, says after the talks that Iran approached the meetings "with a candor" she had not heard in her two years of negotiating with Tehran. The parties agree to meet again November 7-8 in Geneva with an experts level meeting October 30-31.
October 28-29, 2013: Iran meets with the IAEA to continue discussions over the agency's investigations into Iran's past nuclear activities with possible miltiary dimensions. According to a joint statement, Iran presented a new proposal at the talks that contained "practical measures" to "strengthen cooperation and dialouge with a view to future resolutiion of all outstanding issues." Iran and the IAEA agree to meet again in Tehran on November 11.
November 7-10, 2013: The P5+1 and Iran meet in Geneva to continue negotiations over Iran's nuclear program. On November 8, with the expectation that a deal is close, U.S. Secretary of State John Kerry flies to Geneva to join the talks, as do the foreign ministers from the other P5+1 countries. The parties fail to reach an agreement on a first-phase deal, but announce that talks will continue on November 20 in Geneva.
Secretary Kerry says in Nov. 10 press conference that the parties "narrowed the differences" and made significant progress toward reaching an agreemend during the talks.
November 11, 2013: IAEA Director General Yukiya Amano and Ali Akbar Salehi meet in Tehran to continue talks on an approach for the agency's investigations into Iran's past nuclear activities with possible miltiary dimensions. Amano and Salehi sign a Framework for Cooperation Agreement. The framework lays out initial practical steps to be take by Iran within three months, including allowing IAEA access to the Heavy Water Production Plant at Arak and the Gchine uranium mine, and providing the agency with information on new reserach reactors and nuclear power plants that Iran intends to build. The statement commits the parties to cooperation "aimed at ensuring the exclusively peaceful nature of Iran’s nuclear programme through the resolution of all outstanding issues that have not already been resolved by the IAEA."
November 20-24, 2013: Iran and the P5+1 meet again in Geneva to continue negotiations. On November 23, the foreign ministers from the P5+1 join the negotiations. Early on November 24, Iranian Minister Javad Zarif and Catherine Ashton, leader of the P5+1 negotiating team, sign an agreement called the Joint Plan of Action. It lays out specific steps for each side in a six-month, first-phase agreeement, and the broad framework to guide negotiations for a comprehesive solution.
The first-phase pauses further developments in Iran's nuclear program, rolls back significant elements like the stockpile of 20 percent enriched uranium, and requires more extensive IAEA monitoring and access to nuclear sites. In return, Iran receives limited sanctions relief, repatriation of limited assets frozen abroad, and a comittment that no new nuclear-related sanctions will be imposed on Iran for the duration of the agreement. For more details on the agreement, click here.
The plan will establish a Joint Commission to monitor the agreement and work with the IAEA. The six month period can be extended by mutual consent of both parties.
December 8, 2013: Under the terms of the Framework for Cooperation Agreement the IAEA visits the Arak Heavy Water Production Plant.
December 9-12, 2013: The P5+1 and Iran meet in Geneva at the technical level to begin discussions on the implementation of the Nov. 24 Joint Plant of Action.
December 11, 2013: Iran and the IAEA meet again in Vienna to review progress made on the six actions that Iran agreed to take as part of the Framework for Cooperation Agreement. The parties also begin discussing the next practical steps for Iran to take and initially plan to meet again on Jan. 21 to finalize the measures. The meeting is later postponed at the request of Iran to Feb. 8.
December 30-31, 2013: Technical level discussions between Iran and the P5+1 on implementing the Joint Plan of Action continue in Geneva.
January 9-10, 2014: Iran and the P5+1 meet for a third time in Geneva to discuss implementation. The parties reach an agreement and return to their respective capitals for approval.
January 12, 2014: Iran and the P5+1 announce that implementation of the Joint Plan of Action will begin on Jan. 20.
January 20, 2014: Implementation of the Joint Plan of Action begins. The IAEA issues a report on Iran's compliance with the deal. The report states that Iran is adhering to the terms of the agreement, including, halting enrichment of uranium to 20 percent, beginning to blend down half of the stockpile of 20 percent enriched uranium to 3.5 percent, and halting work on the Arak Heavy Water Reactor. The IAEA also begins more intrusive and frequent inspections.
The United States and the European Union also issue statements saying they have taken the necessary steps to waive the specific sanctions outlined in the Nov. 24 deal and release a schedule of payments for Iran to receive oil money held up in the other countries.
February 9, 2014: Iran and the IAEA meet to discuss further actions for Iran to take under the November 11 framework agreement to resolve the agency’s concerns about Iran’s nuclear program. They agree on additional actions, including Iran’s past work on exploding bridgewire detonators, one of the past activities with possible military dimensions.
February 17-20, 2014: Negotiations between Iran and the P5+1 on the comprehensive agreement begin in Vienna. The parties agree on an agenda and framework to guide the talks
March 17-20, 2014: The P5+1 and Iran meet in Vienna to continue negotiations.
April 7-9, 2014: Another round of talks between Iran and the P5+1 take place in Vienna.
May 13-16, 2014: The P5+1 and Iran begin drafting the comprehensive agreement.
May 21, 2014: Iran and the IAEA announce an additional five actions for Iran to complete before August 25. Two of the activities that Iran agrees to provide information on relate to possible military dimensions.
June 2-6, 2014: At the IAEA board meeting Director General Yukiya Amano says that Iran is complying with the terms of the interim agreement and the agency's investigation into the unresolved concerns about Iran's nuclear program. The agency's quarterly report shows that Iran has neutralized nearly all of its stockpile of 20 percent uranium gas bu dilution or conversion to powder form.
June 16-20, 2014: Iran and the P5+1 hold another round of negotiations in Vienna.
July 2-19, 2014: Iran and the P5+1 continue talks in Vienna on a comprehensive nuclear agreement. Early on June 19, the parties announce that they will extend the talks through November 24 and keep the measures agreed to in the interim agreement in place. The parties also announce additional actions that Iran will take, namely converting 25 kg of uranium powder enriched to 20 percent into fuel plates and blending down about 3 tons of uranium enriched to less than 2 percent. The P5+1 will also repatriate $2.8 billion in funds. The parties agree to resume talks in August.
August 25, 2014: Iran misses a deadline to complete actions on five areas of concern to the IAEA as part of the agreement that Iran and the agency reached in November 2013.
September 5, 2014: The IAEA's quarterly report on Iran's nuclear program shows that Iran is complying with the interim deal, but did not provide the IAEA with information about past activities with possible military dimensions (PMDs) by the Aug. 25 deadline.
September 18, 2014: Talks between Iran and the P5+1 resume in New York City on the sidelines of the UN General Assembly. Both sides say that little progress was made at the end of the talks.
October 14-16: Iran and the P5+1 meet in Vienna to continue negotiations. Officials say that they remain focused on reaching an agreement by the Nov. 24 deadline and progress was made during the talks.
November 9-10: Iranian Foreign Minister Zarif and U.S. Secretary of State Kerry meet in Muscat, Oman to continue talks. P5+1 lead negotiator Catherine Ashton is also present.
November 18-24: Iran and the P5+1 meet in Vienna to continue negotiations on an comprehensive agreement. U.S. Secretary of State John Kerry joins the talks on Nov. 20. French Foreign Minister Fabiusu, British Foreign Secretary Hammond, and German Foreign Minister Steinmeier all join the talks between Nov. 20 and 22. Russian Foreign Minister Lavrov arrives on Nov. 23 and Chinese Foreign Minister Wang on Nov. 24.
November 24: Iran and the P5+1 announce that negotiations will be extended because progress was made on the difficult issues and both sides see a path forward. The parties announce that they now aim to reach a political agreement by March and then complete the technical annexes by June 30. Both sides will continue to implement the conditions of the interim Joint Plan of Action from November 2013. Iran and the P5+1 also make additional commitments.
December 15: Talks between the P5+1 and Iran continue in Geneva. U.S. State Department officials say the talks are "good and substanative." Parties plan to meet again in January.
December 24: Iran’s Foreign Minister Mohammad Javad Zarif says in a letter to his foreign counterparts that Iran’s goal remains to reach a comprehensive nuclear deal that assures the world its nuclear program is exclusively peaceful.
January 15-18: The P5+1 and Iran meet in Geneva to continue negotiations.
January 21: In testimony before the Senate Foreign Relations Committee on Jan. 21, U.S. Deputy Secretary of State Antony Blinken says: "We assess that we still have a credible chance of reaching a deal that is in the best interest of America's security, as well as the security of our allies."
January 23-24: Undersecretary of State Wendy Sherman and European Union Political Director Helga Schmid meet again with Iranian Deputy Foreign Minister Abbas Araghchi in Zurich, Switzerland.
February 18-20: Talks between the P5+1 and Iran resume in Vienna.
February 19: A report by the Director General of the IAEA confirms that Iran is upholding its commitments under the interim deal, including additional provisions from the November 2014 extension. The report notes “Iran has continued to provide the Agency with managed access to centrifuge assembly workshops, centrifuge rotor production workshops and storage facilities.”
March 3: Prime Minister Netanyahu delivers a speech to a joint session of Congress. His speech claims that the Iran deal “would all but guarantee that Iran gets [nuclear] weapons, lots of them.”
March 9: Senator Tom Cotton and 46 other senators sign an open letter to the Parliament of Iran. The letter warns that any deal reached without legislative approval could be revised by the next president “with the stroke of a pen.”
March 17-20: Talks between the P5+1 and Iran continue in Lausanne. The head of Iran’s Atomic Energy Organization, Ali Akbar Salehi, says to reporters "We have made progress on technical issues… One or two issues remain and need to be discussed."
March 25-April 2: Negotaitions continue in Lausanne. By March 29, all of the Foreign Ministers from the seven countries involved and EU foreign policy chief Federica Mogherini are present.
April 2: Iran and the P5+1 announce agreement on a general framework that outlines the broad parameters of a nuclear deal. The United States issues a more specific factsheet on the details. Iran and the P5+1 agree to continue meeting to finalize a deal before June 30.
April 14: The Senate Foreign Relations Committee unanimously passes legislation authored by Senator Bob Corker (R-Tenn.) that will require the President to submit the deal to Congress for a vote of approval or disapproval. According to the legislation, the President will not be able to waive sanctions during the 30 day Congressional review period.
April 15: Iran and the IAEA meet in Tehran to continue discussing the agency's investigations into the possibly military dimensions of Iran's nuclear program.
April 27: U.S. Secretary of State John Kerry and Iranian Foreign Minister Mohammad Javad Zarif meet in New York on the sidelines of the nuclear Nonproliferation Treaty Review Conference. Technical drafting work on the annexes of the agreement is underway.
May 7: The Senate passes the Corker legislation 98-1 on congressional review of an Iran nuclear deal.
May 12: EU and Iranian negotiators meet in Vienna to continue drafting a comprehensive ageement.
July 14: Iran and the P5+1 announce a comprehensive deal. Iran and the IAEA announce a roadmap for the agency's investigation into the possible military dimensions of Iran's nuclear program.
July 19: The Obama administration sends the comprehensive deal and supporting documents to Congress, beginning the 60 day review period mandated by the Iran Nuclear Deal Review Act.
July 20: The UN Security Council unanimously passes a resolution endorsing the nuclear deal and the lifting of UN Security Council nuclear sanctions once key steps are taken in the deal.