The head of the Iranian delegation said progress was made in the meeting in Vienna which dealt with the U.N. agency's mounting concerns that Tehran may be seeking to develop the capability to develop nuclear weapons. 

Neither side gave details about the content of the talks and they did not say if they discussed Iran granting U.N. inspectors access to its Parchin military site - where the watchdog suspects nuclear bomb-relevant research has been carried out.

  The meeting tested Iran's readiness to address concerns over possible military aspects to its nuclear work - which it says is entirely peaceful - ahead of negotiations on the program's future in Baghdad on May 23 between Tehran and six world powers. 

The International Atomic Energy Agency (IAEA) had hoped the meeting would secure agreement on access to Iranian sites, documents and officials involved in suspected research that could be put to use producing nuclear explosives.

  "The primary focus of our discussions was how to clarify issues related to possible military dimensions of Iran's nuclear program," IAEA Deputy Director General Herman Nackaerts told reporters after two days of talks at an Iranian diplomatic mission in Vienna.