The International Atomic Energy Agency says Iran has agreed to cooperate in clarifying whether it has tried to develop nuclear weapons. From Paris, Lisa Bryant reports the Vienna-based IAEA hopes Tehran will provide the information in May.

News of Tehran's agreement to cooperate in clarifying whether or not it has been involved in nuclear-weapons development was provided in a brief statement by the IAEA. The IAEA considers the agreement a positive sign. It comes a day after Iran's government described talks with top IAEA investigator Oli Heinonen in Tehran as positive.

The United States and other western powers believe Iran is trying to build a nuclear weapon, but Tehran says its nuclear activities are for purely peaceful purposes - to generate energy.

IAEA head Mohamed ElBaradei

During a March board meeting at IAEA headquarters in Vienna, agency head Mohamed ElBaradei urged Tehran to be forthcoming in addressing foreign intelligence reports that indicate Tehran was developing nuclear weapons.

"Iran continues to maintain that these alleged studies either relate to conventional weapons or are fabricated. However, a full-fledged examination of this issue has yet to take place. The agency has not detected the use of nuclear material in connection with the alleged studies, nor does it have credible information in this regard," said ElBaradei. "I urge Iran to be as active and as cooperative as possible in working with the agency to clarify this matter of serious concern."

The nuclear agency will be seeking clarification on intelligence suggesting that Iran drew up blueprints for missiles that would be able to carry nuclear warheads and that Tehran was researching the construction of an underground site for nuclear bomb tests, among other allegations.