"We will not hesitate to report to the (agency's) board, which will report in its turn to the Security Council, if we see any connection with a military program," Mohamed ElBaradei told a NATO meeting in the Slovak capital Bratislava.
But he said "the jury is still out on Iran," before returning to Vienna where his International Atomic Energy Agency was readying to issue a report on Iran's nuclear program ahead of a meeting of the IAEA's 35-nation board of governors on June 14.
The United States claims Iran is hiding a program to build the bomb and has called for the IAEA, which has been investigating the Iranian program since February 2003, to refer the Islamic Republic to the UN Security Council for possible international sanctions.
But ElBaradei said: "There is no evidence that the Iranian program has some military dimension."
He was speaking at the end of a five-day meeting of NATO's Parliamentary Assembly, which gathered 300 members of parliament from 39 countries -- 26 members of the recently expanded NATO and 13 associate members.
The assembly, which is a consultative body, discussed issues including the situation in Afghanistan and Iraq, the US-led "war on terror", nuclear proliferation and weapons of mass destruction.
ElBaradei repeated here his call for re-thinking the non-proliferation regime currently mandated by the nuclear Non-Proliferation Treaty (NPT) that went into effect in 1970.
"In regard of nuclear proliferation, it is time to reshuffle a security system that encourages the arms' race and to think, out of the box, about a new one that would not rely on nuclear deterence".
The NPT allows the five original nuclear powers -- the United States, Britain, China, France and Russia -- to keep their atom bombs and says that non-nuclear-weapon states should stay free of atomic arms.
"A system that encompasses the 'haves' and the 'have nots' is not viable in the long run," ElBaradei said, calling for a new "global security system."
The parliamentary assembly's president Doug Bereuter called at a press conference closing the meeting for NATO to hold its next summit on enlargement in 2007, at the latest.
"Our first task must be to support the efforts of the remaining candidate countries -- Albania, Croatia and Macedonia -- as they strive for NATO membership," Bereuter said.
The Bratislava event came two months after Slovakia and six other former Soviet-bloc countries joined the North Atlantic Treaty Organization on March 29. Slovakia also was among 10 mainly eastern European countries that also joined the European Union on May 1.
Bereuter had Friday warned Friday when the assembly opened that NATO's mission in Afghanistan could fail unless member states boosted their forces in the war-torn country.
He also said there was a risk that Islamic militants would try to disrupt elections due to be held in Afghanistan in September.
"This is a critical period and it's a question of will of the NATO countries to transfer their forces and equipment to Afghanistan or else we could well face failure," Bereuter said.
NATO Secretary General Jaap de Hoop Scheffer was unable to attend the closing session Tuesday after technical problems forced the cancellation of his flight from Brussels, an official said.
The NATO assembly had opened under tight security in Bratislava on Friday after a scare caused by the discovery of two bags filled with explosives in the Slovak capital.
Some 1,000 police were deployed with another 1,000 on standby for the event.