Vienna: The UN nuclear monitoring agency on Wednesday announced a "milestone" agreement with Iran that aims to provide answers about allegations Tehran tried to develop nuclear weapons under cover of a peaceful atomic programme.

International Atomic Energy Agency spokeswoman Melissa Fleming divulged no details in a brief statement about the deal. But IAEA chief Mohamed ElBaradei called the agreement "a milestone" that, if successful, should signal the end of his organisation's years of attempts to probe Tehran's secretive nuclear program.

"An agreement was reached during the meetings in Tehran on a process that aims to clarify the so-called alleged (nuclear weapons) studies during the month of May," Fleming said in a statement from the Vienna-based agency.


She was alluding to talks Monday and Tuesday between senior Iranian officials and IAEA Deputy Director General Olli Heinonen.

ElBaradei, in Sarajevo before collecting an award from a Bosnian university, said he was hopeful that by the May deadline "we will be in a position to get the explanation and clarification from Iran as to these alleged studies," adding: "This, in my view, is a positive step."

He called the issue "the only remaining topic for us to investigate about past and present Iran nuclear activities" - a statement sure to be challenged by the US and other nations suspicious that Tehran may be hiding an undeclared nuclear program from the agency.