Iran’s more than half a century-old nuclear programme has been at the heart of regional and international tensions, shaping global diplomacy and fuelling sanctions.
Following Israel’s early Friday attack on Iran’s nuclear and military facilities, tensions have surged across the Middle East.
Here is a timeline tracing key developments in Iran’s nuclear programme over the years.
1957:
The United States and Iran, then ruled by Shah Mohammad Reza Pahlavi, who was brought to power by a 1953 CIA coup against the country’s democratically-elected Prime Minister Mohammad Mosaddegh, sign an agreement on civil nuclear cooperation.
1967:
The United States provides Iran with the Tehran Research Reactor (TRR), a 5-megawatt nuclear reactor along with weapon-grade 93 % enriched uranium fuel.
1968:
Iran signs the Nuclear Non-Proliferation Treaty (NPT) which, when ratified two years later, permits
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.
1984:
The US 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.
1996:
The US Congress passes the Iran-Libya Sanctions Act, also known as the Iran Sanctions Act, that penalizes foreign and US investment exceeding $20 million in Iran’s energy sector in one year.
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.
2003:
The International Atomic Energy Agency (IAEA) ordered Iran to suspend uranium enrichment and allow broader inspections. Iran agreed by the October 31 deadline, pledging to halt enrichment and ratify a protocol granting expanded IAEA access.
2004:
After the IAEA rebuked Iran for lack of cooperation, Iran briefly resumed enrichment activities. It later agreed to suspend them again under the Paris Agreement with France, Germany, and the UK, avoiding referral to the UN Security Council.
2005:
Iran resumed uranium hexafluoride production at its Isfahan facility, prompting France, Germany, and the UK to end negotiations. On September 24, the IAEA passed a resolution finding Iran in noncompliance with its safeguards agreement, setting the stage for possible UN Security Council referral.
2006:
Iran enriched uranium for the first time and rejected a P5+1 proposal to halt the program. The UN Security Council responded with Resolutions 1696 and 1737, making suspension legally binding and imposing sanctions for Iran’s noncompliance.
2007:
A US National Intelligence Estimate stated with high confidence that Iran halted its nuclear weapons program in 2003 and likely had not resumed it by mid-2007, though it could be capable of producing weapons-grade uranium between 2010 and 2015.
2009:
Iran launched its first satellite, heightening concerns over its ballistic missile capabilities. That April, the Obama administration shifted US policy by announcing full participation in P5+1 talks with Iran without preconditions. Then the US, UK, and France revealed that Iran had secretly built a second uranium-enrichment facility at Fordow, near Qom, a fact Iran only disclosed to the IAEA after learning it had been discovered. On October 1, Iran and the P5+1 agreed in principle to a US-proposed, IAEA-backed fuel swap for the Tehran Research Reactor, but Iran later sought to alter the deal amid domestic opposition.
2010:
Iran began enriching uranium to 20%, citing the Tehran Research Reactor as the purpose. In response, the UN Security Council, US congress and EU passed a broad package of trade and financial sanctions.
2011:
US intelligence assessed that Iran had not decided to build nuclear weapons but was preserving the option by advancing its capabilities. Iran announced plans to triple its 20% uranium enrichment using advanced centrifuges and move production to the Fordow facility. Meanwhile, the IAEA released a report outlining suspected nuclear weapons-related activities Iran pursued before 2004.
2012:
The EU agreed to ban Iranian oil imports and related insurance starting July 1, increasing pressure on Iran. The IAEA and Iran began discussions on suspected military aspects of Iran’s nuclear program, while Iran and the P5+1 held “positive” talks in Istanbul, agreeing to continue negotiations. The IAEA reported Iran had increased 20 % uranium enrichment beyond TRR needs and was expanding centrifuge installations at Fordow and Natanz.
2013:
Hassan Rouhani, a former nuclear negotiator, was elected president of Iran and pledged greater transparency while maintaining the country’s nuclear program. In a historic development, President Obama called Rouhani—the highest US-Iran contact since 1979, expressing hope for a comprehensive resolution despite major challenges.
2014:
Implementation of the Joint Plan of Action began, with the IAEA confirming Iran’s compliance, including halting 20 % uranium enrichment, diluting part of its enriched stockpile, and pausing work at the Arak reactor. The IAEA also initiated more frequent inspections. Despite this, Foreign Minister Zarif reiterated Iran’s commitment to achieving a comprehensive deal ensuring the peaceful nature of its nuclear program.
2015:
The IAEA confirmed Iran’s compliance with the interim nuclear deal, including expanded access to key nuclear facilities. Iran’s Supreme Leader and parliament approved the deal, and the IAEA Board of Governors ended its investigation into Iran’s past weaponization activities by terminating previous resolutions.
2016:
The IAEA verified Iran’s compliance with the nuclear deal, triggering sanctions relief under UNSC Resolution 2231.Obama hailed the JCPOA as a step toward global security; Rouhani said Iran’s nuclear rights were recognised. Despite compliance, Iran tested ballistic missiles and the US extended the Iran Sanctions Act for 10 years.
2017:
Defense Secretary Mattis backed the JCPOA, saying the US must honour its commitments despite flaws. Iran received Airbus jets, but missile tests led to new US non-nuclear sanctions. Trump waived nuclear sanctions but decertified Iran’s compliance and demanded tougher legislation.
2018:
The US, under President Donald Trump, breached the JCPOA in May, unilterally withdrawing from the treaty and reimposing sweeping sanctions on Iran despite opposition from other signees of the pact.
Iran opened a new centrifuge facility but stayed within JCPOA limits. Israel accused Iran of hiding nuclear material, urging IAEA inspections.
2019:
Iran said it would exceed uranium enrichment caps and limits under the JCPOA. The US accused Iran of Gulf tanker attacks and the Saudi Aramco strike, which Iran denied.
2020:
The US killed General Soleimani; Iran abandoned JCPOA limits on enrichment and centrifuges. Sanctions waivers for nuclear cooperation projects were revoked by Washington. Satellite imagery showed mysterious new construction at the Fordow enrichment site.
2021:
Iran’s parliament passed the Strategic Action Law, halting the Additional Protocol and resuming 20% uranium enrichment, effectively abandoning JCPOA commitments. Indirect talks with the US began in March but paused after Ebrahim Raisi’s election in June.
In April, Iran began enriching uranium to 60%, heightening international concern.
By August, a draft deal was rejected by Khamenei despite reported US concessions, including lifting sanctions on Iranian leaders.
2022:
Talks between Iran and the US, led by Ali Bagheri Kani and Robert Malley, ended without agreement. Amid a violent crackdown on nationwide protests in Iran, Washington declared it was no longer pursuing nuclear diplomacy with Tehran.
2025:
Nuclear talks resumed between Iran and the US under President Trump, despite earlier condemnation from Khamenei. Tensions escalated in May and June as Trump warned of possible military conflict and Iran’s uranium stockpile hit 408.6 kg at 60% purity.
The IAEA passed a resolution raising the threat of UN referral, prompting a sharp response from Iran. As talks were set for Sunday in Oman, the US evacuated non-essential staff, citing Israeli strike preparations.
Israel attacked Iran on June 13, under the pretext of blocking Tehran’s nuclear weapon ambitions, despite Tehran’s long-standing insistence that its nuclear programme is purely for civilian purposes.
