The Iranian foreign ministry said Sunday the country's leadership was re-examining its cooperation with the IAEA after it gave Tehran until October 31 to prove it is not running a secret nuclear weapons programme.
"The nature of our cooperation with the IAEA is under consideration. The relevant authorities are discussing that and our decision will be made public in the future," foreign ministry spokesman Hamid Reza Asefi told reporters.
But Ali Akbar Salehi, Iran's ambassador to the IAEA, went a step further, telling Germany's Der Spiegel magazine that Iran could halt all cooperatiopn with the body and "maybe withdraw from the Nuclear Non-Proliferation Treaty (NPT)".
The NPT demands that signatory nations like Iran do not develop nuclear weapons.
The 35-nation IAEA board of governors on Friday set a deadline on the Islamic republic to prove it is not secretly developing nuclear weapons by enriching uranium.
Analysts said only enormous international pressure on Iran would force it to come clean on its atomic ambitions.
"A lot of pressure has been put on Iran for the last several years to no great effect," William Hopkinson of London's Royal Institute of International Affairs told AFP.
"If the rest of the world joins in so that it is the United States, Russia and the Europeans together, that would start to hurt."
Iran denies manufacturing nuclear weapons and says its nuclear program is only for peaceful purposes.
The IAEA resolution, pushed by the United States, was supported by key nations Britain, France and Germany.
IAEA chief Mohamed ElBaradei has warned Iran the IAEA could declare it to be in non-compliance with the NPT if it failed to answer all the agency's questions on its atomic program by the October 31 deadline.
If the IAEA frins Iran in non-compliance of the nuclear accords, it could bring the issue to the UN Security Council, which has the power to impose punishing sanctions on the Islamic republic.
Hopkinson said he thought the only possible way to pressure Iran was through UN sanctions, with all the "major players" lined up against Tehran.
Analysts said Iran is an different situation to North Korea which the IAEA took to the Security Council in February over non-compliance after Pyongyang kicked out IAEA inspectors, cut off all cooperation with the agency and withdrew from the NPT.
North Korea already has some nuclear bombs, while Iran still wants to raise its military capabilities to match Israel's, which has nuclear weapons, said Christopher Aaron, editor of Jane's Intelligence Review.
Israeli intelligence has alleged that Iran is close to getting nuclear weapons.
Major General Ze'evi Farkash, head of Israeli military intelligence (AMAN), told the London-based Jane's Intelligence Review that once Iran "has the ability to produce enough enriched uranium, we estimate that the first bomb will be constructed within two years, that is the end of 2006 or the beginning of 2007.
"We, though, are relating to the earlier year 2004. Israel views that as the point of no return, that is the moment when all the necessary knowledge will be within the grasp of Iranian scientists," Farkash said.