VIENNA The U.N. nuclear watchdog and Iran began talks on Monday ahead of a deadline later this week for Tehran to provide information about the development of detonators that can be used to help set off an atomic device.
The Iran-IAEA meeting took place a day before the Islamic Republic and six world powers on Tuesday start, also in the Austrian capital, a new round of negotiations on a broad diplomatic settlement of the decade-old nuclear dispute.
Reza Najafi, Iran's envoy to the International Atomic Energy Agency, made no comment as he arrived shortly after 3 p.m. (1300 GMT) at the U.N. agency's Vienna headquarters for Monday's meeting with senior IAEA officials.
Under a transparency and cooperation pact agreed between the two sides in November, Iran was to take seven practical measures by May 15 in a phased process to help allay international concern about its nuclear program.
Diplomatic sources told Reuters on Friday that the IAEA was seeking further clarification from Iran about one of those steps, concerning fast-acting detonators that can have both military and civilian applications.
Iran says it has already implemented the seven steps - including access to two uranium sites - but the sources suggested the IAEA still wanted more information about the so-called Explosive Bridge Wire (EBW) detonators.
How Iran responds to questions about its development and need of this type of equipment is seen as an important test of its willingness to cooperate fully with a long-stalled IAEA investigation into suspected atomic bomb research by Tehran.
Iran says allegations of such work are baseless, but has offered to help clear up the suspicions with the U.N. agency.
The diplomatic sources said Iran had provided an explanation about the detonators, which it says are for non-nuclear uses, and that the IAEA had posed follow-up questions.
They said the IAEA also wanted to agree with Iran new measures to be taken after May 15, hoping these will tackle other sensitive issues linked to what the agency calls the possible military dimensions to Iran's nuclear program.
Iran's talks with the IAEA and with big powers are closely linked as both focus on fears that Iran may be covertly seeking the capability to develop nuclear weapons. Iran says its uranium enrichment program is a peaceful energy project only.
Western diplomats say Iran must start engaging with the IAEA's investigation and that this is central to the success of the powers' talks with Tehran aimed at an accord by late July.
Iran wants an end to sanctions severely hurting its oil-reliant economy. After years of an increasingly vitriolic and confrontational standoff with the West, the election last year of pragmatist Hassan Rouhani as Iran's president created a new atmosphere more conducive to settling disputes via diplomacy.
But diplomats and experts say Iran and the West remain far apart on what a long-term deal to resolve the dispute, and dispel fears of a new Middle East war, would look like.
(Editing by Mark Heinrich)