The head of the International Atomic Energy Agency says Iran is a "special case" for the agency's monitoring teams because of suspicions the country is hiding experimental nuclear programs.
Speaking at the opening of an agency conference Monday in Vienna, IAEA chief Yukiya Amano said Iranian officials have not provided the necessary cooperation for the IAEA to confirm that all nuclear material in Iran is for peaceful activities.
Delegates at the week-long IAEA conference are expected to discuss Iran and Syria's nuclear programs. Arab countries have also succeeded in putting Israel on the group's agenda for the first time since 1991.
Israel is widely believed to have nuclear weapons, but maintains a policy of refusing to acknowledge its nuclear arsenal.
The IAEA conference comes as the U.N. Security Council prepares to vote on a fourth round of sanctions against Iran for its nuclear activities.
On Sunday, U.S. Secretary of State Hillary Clinton said she expects Iran to "pull some sort of stunt" in the next day or two to divert attention from the pending U.N. vote.
Clinton said Iran has done everything possible to avoid international responsibilities involving its nuclear program.
The U.N. Security Council has passed three sets of sanctions against Iran for its refusal to stop enriching uranium, a process that can be used to produce atomic weapons.
The United States and its Western allies accuse Iran of trying to make a nuclear weapon. Iran says its atomic program is for peaceful purposes.
Some information for this report was provided by AP, AFP and Reuters.