Iran is not known to currently possess weapons of mass destruction (WMD) and has signed treaties repudiating the possession of WMD including the Biological Weapons Convention, the Chemical Weapons Convention, and the Non-Proliferation Treaty (NPT). Iran has first-hand knowledge of WMD effects—over 100,000 Iranian troops and civilians were victims of chemical weapons during the 1980s Iran–Iraq War.
In 2003 the Supreme Leader of Iran, Ayatollah Ali Khamenei, along with other clerics, issued a public and categorical religious decree ("fatwa") against the development, production, stockpiling and use of nuclear weapons, though it is approved by some relatively minor clerics. Later versions of this fatwa forbid only the "use" of nuclear weapons, but said nothing about their production. Iran has stated its uranium enrichment program is exclusively for peaceful purposes. The IAEA has confirmed the non-diversion of declared nuclear material in Iran but has also said it "needs to have confidence in the absence of possible military dimensions to Iran’s nuclear program."
In December 2014, a Wisconsin Project on Nuclear Arms Control report by Lincy and Milhollin based on IAEA data concluded that Iran could produce enough weapons-grade uranium for one nuclear warhead in 1.7 months.
In 2012, sixteen U.S. intelligence agencies, including the CIA, reported that Iran was pursuing research that could enable it to produce nuclear weapons, but was not attempting to do so. In 2010 and 2011, the senior officers of all of the major American intelligence agencies stated that there was no conclusive evidence that Iran has made any attempt to produce nuclear weapons since 2003. In a 2007 National Intelligence Estimate, the United States Intelligence Community assessed that Iran had ended all "nuclear weapon design and weaponization work" in 2003. Then U.S. Defense Secretary Leon Panetta stated in January 2012 that Iran was pursuing a nuclear weapons capability, but was not attempting to produce nuclear weapons. In 2009, U.S. intelligence assessed that Iranian intentions were unknown. Some European intelligence believe Iran has resumed its alleged nuclear weapons design work. In 2011, then Russian president Dmitry Medvedev said Iran was close to having the capability to produce nuclear weapons. Iran has called for nuclear weapons states to disarm and for the Middle East to be a nuclear weapon free zone. 
After the IAEA voted in a rare non-consensus decision to find Iran in non-compliance with its NPT Safeguards Agreement and to report that non-compliance to the UN Security Council, the Council demanded that Iran suspend its nuclear enrichment activities and imposed sanctions against Iran when Iran refused to do so. Former Iranian president Mahmoud Ahmadinejad argued that the sanctions were illegal. The IAEA has been able to verify the non-diversion of declared nuclear material in Iran, but not the absence of undeclared activities. The Non-Aligned Movement has called on both sides to work through the IAEA for a solution.
In November 2009, the IAEA Board of Governors adopted a resolution against Iran which urged Iran to apply the modified Code 3.1 to its Safeguard Agreement, urged Iran to implement and ratify the Additional Protocol, and expressed "serious concern" that Iran had not cooperated on issues that needed "to be clarified to exclude the possibility of military dimensions to Iran's nuclear program." Iran said the "hasty and undue" resolution would "jeopardize the conducive environment vitally needed" for successful negotiations.
Nuclear weapons.
Overview.
In September 2005, the IAEA Board of Governors, in a rare non-consensus decision with 12 abstentions, recalled a previous Iranian "policy of concealment" regarding its enrichment program ;ref name="IAEA-GOV/2003/75" ; ;/ref ; and found that Iran had violated its NPT Safeguards Agreement. ;ref name="IAEA-GOV/2005/77" ; ;/ref ; Another IAEA report stated "there is no evidence that the previously undeclared nuclear material and activities ... were related to a nuclear weapons program." Iran has claimed that the military threat posed by Israel and the United States is forcing it to restrict the release of information on its nuclear program. Gawdat Bahgat of the National Defense University speculates that Iran may have a lack of confidence in the international community which was reinforced when many nations, under pressure from the United States, rejected or withdrew from signed commercial deals with the Iranian nuclear authority.
On 31 July 2006, the UN Security Council passed a resolution demanding Iran suspend its enrichment program. On 23 December 2006, the Security Council imposed sanctions against Iran, which were tightened on 24 March 2007, because Iran refused to suspend enrichment. Iran's representative to the UN argued that the sanctions compelled Iran to abandon its rights under the NPT to peaceful nuclear technology. The Non-Aligned Movement called on both sides to work through the IAEA for a solution.
US intelligence predicted in August 2005 that Iran could have the key ingredients for a nuclear weapon by 2015. On 25 October 2007, the United States declared the Revolutionary Guards a "proliferator of weapons of mass destruction", and the Quds Force a "supporter of terrorism". Iran responded that "it is incongruent for a country [US] who itself is a producer of weapons of mass destruction to take such a decision." Mohamed ElBaradei, Director General of the IAEA at the time, said he had no evidence Iran was building nuclear weapons and accused US leaders of adding "fuel to the fire" with their rhetoric. Speaking in Washington in November 2007, days before the IAEA was to publish its latest report, Israeli deputy prime minister Shaul Mofaz called for ElBaradei to be sacked, saying: "The policies followed by ElBaradei endanger world peace. His irresponsible attitude of sticking his head in the sand over Iran's nuclear programme should lead to his impeachment." Israel and some western governments fear Iran is using its nuclear programme as a covert means to develop weapons, while Iran says it is aimed solely at producing electricity. For its part in the conflict-ridden Middle East, Israel is a member of the IAEA, but it is not itself a signatory to the Nuclear Non-Proliferation Treaty, and is widely believed to currently be the only nuclear-armed state in the region.
History.
Iran's nuclear program began as a result of the Cold War alliance between the United States and the Shah of Iran, Mohammad Reza Pahlavi, who emerged as an important US ally in the Persian Gulf. Under the Atoms for Peace program, Iran received basic nuclear research facilities from the United States. In return, Tehran signed the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) in 1968. Fueled by high oil prices in the 1970s, Iran sought to purchase large-scale nuclear facilities from Western suppliers in order to develop nuclear power and fuel-cycle facilities with both civilian and potential military applications. In March 1974, the shah established the Atomic Energy Organization of Iran (AEOI). Sensing a heightened risk of nuclear proliferation, the United States convinced Western allies to limit the export of nuclear fuel-cycle facilities to Iran. Supreme Leader Ayatollah Ruhollah Khomeini, whose revolution displaced the Shah's monarchy in 1979 and ruled the newly established Islamic Republic of Iran until his death in 1989, placed little emphasis on nuclear weapons development because it was viewed as a suspicious Western innovation. During that time, many of Iran's top scientists fled the country while the United States organized an international campaign to block any nuclear assistance to Iran.
Following the death of Ayotollah Khomeini, the leadership of President Ali Akbar Hashemi Rafsanjani and Supreme Leader Ali Hosseini Khamenei sought to revive Iran's overt nuclear civilian program and expand undeclared nuclear activities during the 1990s. According to a strategic dossier from International Institute for Strategic Studies, Iran turned away from Western suppliers and obtained nuclear assistance from Russia and China in a number of key areas, including uranium mining, milling and conversion, as well as technology for heavy-water research reactors. However, Washington intervened with Moscow and Beijing to prevent Iran from fully acquiring its list of nuclear power and fuel-cycle facilities. The 1990s also saw Iran expand its furtive nuclear research into conversion, enrichment and plutonium separation. "Most importantly, on the basis of additional centrifuge assistance from the A.Q. Khan network, Iran was able to begin the construction of pilot-scale and industrial-scale enrichment facilities at Natanz around 2000." Full exposure of Iran's nuclear activities came in 2002, when an Iranian exiled opposition group, the National Council of Resistance of Iran (NCRI) declared the Natanz project in August of that year. Since that time, international pressure on Iran has remained steady, hampering but not halting the country's nuclear development. Iran remains legally bound to the NPT and states its support for the treaty.
There are various estimates of when Iran might be able to produce a nuclear weapon, should it choose to do so:
IAEA.
The International Atomic Energy Agency (IAEA) is an autonomous international organization that seeks to promote the peaceful use of nuclear energy and to inhibit its use for military purposes.
On 6 March 2006, the IAEA Secretariat reported that "the Agency has not seen indications of diversion of nuclear material to nuclear weapons or other nuclear explosive devices ... however, after three years of intensive verification, there remain uncertainties with regard to both the scope and the nature of Iran's nuclear programme". However, the inspectors did find some sensitive documents, including instructions and diagrams on how to make uranium into a sphere, which is only necessary to make nuclear weapons. Iran furnished the IAEA with copies, claiming not to have used the information for weapons work, which it had obtained along with other technology and parts in 1987 and the mid-1990s. It is thought this material was sold to them by Abdul Qadeer Khan, though the documents did not have the necessary technical details to actually manufacture a bomb.
On 18 December 2003, Iran voluntarily signed, but did not ratify or bring into force, an Additional Protocol that allows IAEA inspectors access to individuals, documentation relating to procurement, dual-use equipment, certain military-owned workshops, and research and development locations. ;ref name="IAEA-GOV/2005/87" ; ;/ref ; Iran agreed voluntarily to implement the Additional Protocol provisionally, however when the IAEA reported Iran's non-compliance to the United Nations Security Council on 4 February 2006 Iran withdrew from its voluntary adherence to the Additional Protocol.
On 12 May 2006, claims that highly enriched uranium (well over the 3.5% enriched level) was reported to have been found "at a site where Iran has denied such sensitive atomic work", appeared. "They have found particles of highly enriched uranium [HEU], but it is not clear if this is contamination from centrifuges that had been previously found [from imported material] or something new," said one diplomat close to the UN International Atomic Energy Agency (IAEA). These reports have not yet been officially confirmed by the IAEA (as of 1 June 2006).
On 31 July 2006, the United Nations Security Council passed a resolution demanding that Iran suspend its uranium enrichment activities.
In late 2006, "New traces of plutonium and enriched uranium– potential material for atomic warheads– have been found [by the IAEA] in a nuclear waste facility in Iran." However, "A senior U.N. official who was familiar with the report cautioned against reading too much into the findings of traces of highly enriched uranium and plutonium, saying Iran had explained both and they could plausibly be classified as byproducts of peaceful nuclear activities." In 2007 these traces were determined to have come from leaking used highly enriched uranium fuel from the Tehran Research Reactor, which the U.S. supplied to Iran in 1967, and the matter was closed. ;ref name="IAEA-GOV/2007/48" ; ;/ref ;
In July 2007 the IAEA announced that Iran has agreed to allow inspectors to visit its Arak nuclear plant, and by August 2007 a plan for monitoring the Natanz uranium enrichment plant will have been finalised.
In August 2007 the IAEA announced that Iran has agreed to a plan to resolve key questions regarding its past nuclear activities. The IAEA described this as a "significant step forward".
In September 2007 the IAEA announced it has been able to verify that Iran's declared nuclear material has not been diverted from peaceful use. While the IAEA has been unable to verify some "important aspects" regarding the nature and scope of Iran's nuclear work, the agency and Iranian officials agreed on a plan to resolve all outstanding issues, Director-General Mohamed ElBaradei said at the time. In an interview with Radio Audizioni Italiane the same month, ElBaradei remarked that "Iran does not constitute a certain and immediate threat for the international