The UN nuclear watchdog said on Monday it had not been able to make much progress on the issue of a possible military aspect to Iran''s nuclear program.

"Regrettably, the Agency has not been able to make substantive progress on the alleged studies and associated questions relevant to possible military dimensions to Iran''s nuclear program. These remain of serious concern," said Mohamed ElBaradei, the head of the International Atomic Energy Agency (IAEA).

He said Iran had so far produced only limited quantities of low enriched uranium, and "this is still a cause for concern for the international community in the absence of full clarity about Iran''s past and present nuclear program."

He said the agency "does not in any way seek to ''pry'' into Iran''s conventional or missile-related military activities. Our focus is clearly on nuclear material and activities. We need, however, to make use of all relevant information to be able to confirm that no nuclear material is being used for nuclear weapons purposes."

ElBaradei urged Iran to show full transparency and implement all measures required "to build confidence in the exclusively peaceful nature of its nuclear program at the earliest possible date."