It will be the fourth satellite sent into space since 2009 by Iran, whose space program has attracted the concern of international community which is suspecting Tehran is seeking to develop long-range ballistic missiles capable of carrying conventional warheads or nuclear ones.

This is the first time that the Islamic republic has announced in advance a date for the launch of a satellite. Previous launches were reported after the operations were successfully undertaken.

On May 23 Iran opens talks with world powers in Baghdad over Tehran's disputed nuclear program which has been denounced by several members of the UN Security Council. The Security Council has imposed on Iran an almost total embargo on nuclear and space technologies since 2007.

Part of the international community, namely the West, suspects Iran, despite its denials, of seeking to develop nuclear weapons with the ultimate goal to be able to equip its missiles. Iran's previous satellite launches triggered condemnation from the West who accused Tehran of "provocation."

The Fajr (Dawn) satellite was presented by the Iranian officials as "an observation and measurement" satellite weighing 50 kg, built by Sa-Iran, a company affiliated to the Defense Ministry.

Meanwhile, the UN nuclear watchdog signaled yesterday it would press Iran for access to a military facility where it suspects the Islamic state has built a chamber for high-explosive tests that could serve a bid to develop nuclear weapons.

Iran, which rejects Western accusations it seeks atomic arms, has so far resisted requests by the International Atomic Energy Agency (IAEA) to visit the extensive Parchin complex southeast of Tehran. The issue was expected to be raised during a high-level May 14-15 Vienna meeting between Iran and the IAEA.

An IAEA report last November found Iran had built a large containment vessel in 2000 at the site in which to conduct high-explosive tests that the UN agency said were "strong indicators of possible (nuclear) weapon development."

"A building was constructed at that time around a large cylindrical object ... A large earth berm was subsequently constructed between the building containing the cylinder and a neighboring building, indicating the probable use of high explosives in the chamber."

The IAEA said it had obtained satellite images that were consistent with this information. The vessel was designed to contain the detonation of up to 70 kg of high explosives.

Western diplomats say they suspect Iran may be cleaning the location to remove incriminating evidence before inspectors can go there. A US security institute said last week satellite imagery showed activity there which it said raised concern that Iran may be "washing" the building the IAEA wants to see.

Iran's ambassador to the IAEA has previously dismissed such suspicions about Parchin as "childish" and "ridiculous."

Herman Nackaerts, IAEA deputy director general, said Iran must give his inspectors access to sites, information and people as he began the two-day meeting with Iranian officials on the country's disputed atomic activities.

The talks in Vienna will test Iran's readiness to address U.N. inspectors' suspicions of military dimensions to its nuclear program, ahead of high-stakes talks on the program in Baghdad next week between Iran and six world powers.

Two previous rounds of talks in Tehran this year with UN inspectors failed to make any notable progress, especially on their request to go to Parchin.

"The aim ... is to reach agreement on an approach to resolve all outstanding issues with Iran," Nackaerts told reporters as he arrived at an Iranian diplomatic mission in a smart area of Vienna.

"In particular, clarification of the possible military dimensions remains our priority ... It is important now that we can engage on the substance of these issues and that Iran let us have access to people, documents, information and sites."