The International Atomic Energy Agency has begun a five-day meeting in Vienna to examine Iran's nuclear activities, as well as suspicions that Syria secretly might have tried to build a nuclear reactor.
Iran insists that its atomic program is peaceful and says it could limit its cooperation with the U.N.'s nuclear watchdog after the agency's latest critical report of Tehran.
The IAEA report issued last week said Iran has not provided enough evidence to refute that it is trying to make nuclear weapons.
U.N. atomic watchdog chief Mohamed ElBaradei also criticized Israel and the U.S. at Monday's meeting for not passing on intelligence about Syria's alleged nuclear reactor and attacking the site before the agency had a chance to inspect it.
He told IAEA's 35-member board that it was regrettable that force was resorted to unilaterally before the agency had an opportunity to establish the facts in Syria.
Syria has denied any illegal activity and has agreed to let inspectors into the country this month.
The inspectors will investigate the site that Israeli warplanes destroyed in September.
Some information for this report was provided by AFP, AP and Reuters.