The IAEA report said that "extensive activities" at the Parchin military compound - an allusion to suspected Iranian attempts to remove evidence - would seriously undermine an agency investigation into indications that research relevant to developing a nuclear explosive were conducted there.
The IAEA delivered its latest quarterly Iran report 10 days after U.S. President Barack Obama's re-election raised hopes of a revival of nuclear diplomacy with Iran following speculation that Israel might bomb Iranian nuclear facilities.
Iran denies aiming to acquire nuclear weapons, saying its atomic programme is solely for peaceful energy purposes.
Iran is ready to sharply expand its uranium enrichment in an underground site after installing all the centrifuges it was built for, a U.N. nuclear report showed, a development likely to fuel Western alarm over Tehran's nuclear aims.
The Islamic state has put in place nearly 2,800 centrifuges that the Fordow enrichment site, buried deep inside a mountain, was designed for and could soon double the number of them operating to almost 1,400, according to an International Atomic Energy Agency report obtained by Reuters.
Israel is facing growing international pressure not to attack Iran unilaterally, with the US in particular making clear its firm opposition to any such strike. It follows pressure on world leaders to halt Iran's contested nuclear programme.
The US Chairman of the Joint Chiefs of Staff General Martin Dempsey made comments that Washington did not want to be blamed for any Israeli initiative, according to an interview with the Guardian.
I don't want to be complicit if they (Israel) choose to do it. (This) could be undone if (Iran) was attacked prematurely.
– Martin Dempsey, US chairman of the Joint Chiefs of Staff General
A report by the UN's nuclear watchdog that accused Iran of doubling the number of uranium enrichment entrifuges it has in an underground bunker was politically motivated, as Iranian lawmaker said today.
The International Atomic Energy Agency (IAEA) report yesterday indicated that despite threat of an Israeli or US military strike on Tehran's nuclear facilities, it was rapidly increasing the enrichment capacity of its Fordow site, buried deep underground to withstand any such hit.
"Publishing this report while Iran is holding the Non-Aligned Movement (NAM) meeting does not mean anything other than it was a political move aimed at overshadowing the meeting in Tehran," lawmaker Kazem Jalali told the ISNA news agency.
Every incremental increase brings Iran closer to the day when it could produce a nuclear weapon, should it make the political decision to do so. They're not there yet, this is an incremental increase... But it would certainly be seen as concerning in Israel and parts of the US.
– Mark Fitzpatrick. International Institute for Strategic Studies
Iran's supreme leader says the country will not abandon its "peaceful" atomic program. The United States and its allies suspect Iran is trying to develop nuclear weapons, a charge Tehran denies.
I declare that the Islamic Republic of Iran has never been after nuclear weapons and it will never abandon its right for peaceful use of nuclear energy. Nuclear arms have neither provided security nor boosted political power.
– Ayatollah Ali Khamenei
Ayatollah Ali Khamenei has the final say on all state matters in Iran.