Ministers from the 15 EU states and the 10 future members, in a meeting Monday, will urge Tehran to unconditionally sign an additional protocol of the Nuclear Non-Proliferation Treaty (NPT) which would formalize the probe by the UN nuclear agency, the International Atomic Energy Agency (IAEA), the source said, according to Agence France-Presse (AFP).

At present inspectors only have the authority to see declared nuclear facilities.

Their meeting in Luxembourg will coincide with the opening of a key IAEA session in Vienna which will hear a report saying Iran has failed to honor its nuclear safeguards agreement, and decide what message to send to Tehran's government.

Washington, which maintains Iran is hiding a nuclear weapons program, has also called for a strong resolution of concern to be passed by the IAEA's 35-nation board of governors.

Britain has already come aboard the U.S.-led campaign to urge Tehran to take a confidence-building step regarding its nuclear intentions, but the EU pressure comes with the added incentive of lucrative trade and commercial ties.

Last December the European bloc opened talks with Iran on economic cooperation, but its top diplomats are likely to recall on Monday that any deal with the Islamic regime is contingent upon political reforms.

"Deepening the EU's economic and business ties with Iran must be done parallel to progress in other areas of (bilateral) relations," the diplomatic source said, naming those areas as "human rights, non-proliferation, terrorism and the Middle East".

"The message from ministers to the Iranians will be that the most important thing at the present stage is that Iran signs urgently and unconditionally the additional protocol with the International Atomic Energy Agency (IAEA)," the source said.

On Tuesday the head of Iran's atomic energy body, Gholam Reza Aghazadeh, said that the country was not concealing any of its facilities from the UN nuclear inspectors.

But a U.S. State Department official said Wednesday the IAEA report was a "devastating" indictment of Iran's intentions that was fully consistent with U.S. accusations and a cause for global alarm.

A summary of the report obtained by AFP - the result of five months of IAEA inspections - says that Tehran has not upheld its obligations, but it does not seem to reach Washington's more dire conclusions.

In it, IAEA head Mohamed ElBaradei found Iran to have violated the NPT but was also taking steps to come back into compliance.

‘No Place" In Iran's Strategy

In Tehran, meanwhile, a senior Iranian security official asserted Saturday that nuclear weapons had no place in the country's defensive strategy, in the latest bid to ease suspicions the Islamic republic is seeking to acquire the atomic bomb.

"Weapons of mass destruction have no place in Iran's security strategy," Hassan Rowhani, who heads Iran's Supreme Council on National Security, was quoted as saying by the official news agency IRNA.

"One of the most important elements of Iran's Middle East policy consists of the region being free of weapons of mass destruction," he was quoted as telling a visiting Japanese government envoy.

He also demanded the "destruction of the arsenal of the Zionist regime (Israel), which is packed with weapons of mass destruction."