VIENNA: Iran angrily stayed away Monday from a UN atomic agency forum on creating a Middle East free of nuclear weapons, amid growing tensions over Tehran's suspected efforts to develop the bomb.

Iran's ambassador to the Vienna-based International Atomic Energy Agency (IAEA), Ali Asghar Soltanieh, said Tehran's decision was its "first reaction" to the body's "inappropriate" recent report on its nuclear programme.

That assessment saw the IAEA come the closest yet to accusing Iran outright of seeking to develop nuclear weapons. Iran, hit by four rounds of UN sanctions, says its activities are exclusively for peaceful purposes.

On Friday, the IAEA's board of governors passed a resolution of "deep and increasing concern" submitted by the five permanent members of the UN Security Council, Germany and 12 others in light of the report.

Israeli Defence Minister Ehud Barak meanwhile provided an ominous response Sunday when asked about growing speculation of a military strike.

The IAEA report "has a sobering impact on many in the world, leaders as well as the publics, and people understand that the time has come," he told CNN.

"Our greatest wish is that they commit such a mistake," Iranian Revolutionary Guards commander Amir-Ali Hajizadeh was quoted as saying by the Fars news agency on Monday.

Soltanieh said another reason for not attending the two-day IAEA forum, aimed at learning from the experiences of other so-called nuclear-weapon-free zones (NWFZ), was Israel's unofficial atomic arsenal.

"As long as the Zionist regime does not belong to the NPT (nuclear non-proliferation treaty)... this kind of conference is useless and cannot succeed," Soltanieh told Iranian television channel Al-Alam.

Israel is widely believed to possess nuclear weapons but has never confirmed it. Unlike Iran it is not a signatory to the NPT and therefore not subject to IAEA inspections.

Syria, reported by the IAEA to the Security Council over a suspected covert reactor allegedly bombed by Israel in 2007, was however present at the forum, along with Israel, 17 other Middle East states and Palestinian representatives.

Some of the roughly 275 participants from 97 countries in the closed-doors discussion said representatives of several Arab states, particularly Syria and Lebanon, had used their speeches to attack Israel.

"Israeli nuclear capabilities pose a grave and continuous threat to others in the region. Israel must join the NPT," Syria's ambassador Bassam Sabbagh said, according to a participant.

Israel's ambassador was yet to speak. Participants said the atmosphere was however less "confrontational" than previous IAEA events that have degenerated into Arab-Israeli slanging matches.

NWFZ treaties prohibit the production, acquisition and stationing of nuclear weapons, as well as nuclear testing.

Zones of this kind already exist in Latin America and the Caribbean, the South Pacific, Southeast Asia, Africa and Central Asia, encompassing 113 countries.

IAEA member states requested in 2000 that such a Mideast forum take place but agreement on holding such a meeting remained elusive until now.

The forum comes ahead of a conference in 2012 to be hosted by Finland on ridding the powder keg region, rocked this year by Arab Spring popular uprisings in several countries, of nuclear weapons.

IAEA head Yukiya Amano, opening the forum, conceded there were "long-standing differences of view" on creating such a zone.

"It has taken 11 years to get to this point," Amano said. "I hope it will nurture fresh thinking -- creative thinking."

"It's up to Iran to consider if it can make a contribution. Clearly they felt not," South Africa's IAEA ambassador Abdul Samad Minty told reporters.

"But this (the forum) is a first step. It's not the end of the process."