Iran has threatend full-scale uranium enrichment if its nuclear work is referred to the UN Security Council.

The defiance came ahead of the UN atomic watchdog meeting in Vienna that is expected to clear the way for possible action against Tehran over suspicions that it's  seeking nuclear weapons.

Ali Larijani, the Islamic republic's top nuclear negotiator, said on Sunday that Iran would not freeze small-scale nuclear fuel work even if referred to the world body.

"Going to the Security Council will certainly not make Iran go back on research and development," Larijani told reporters in Tehran, adding that the Islamic republic would retaliate to such a move by pressing ahead with full-scale uranium enrichment.

Larijani said, however, that Iran was not intending to use oil as a weapon in the dispute or quit the nuclear Non-Proliferation Treaty (NPT), but warned this could change if the crisis worsened.

US reaction

The US reaction was quick, with a senior official saying that Iran faces "tangible and painful consequences" if it continues its nuclear activities and the United States will use "all tools at our disposal" to stop this threat.

The warning was made by John Bolton, the US Ambassador to the United Nations, at a convention of Jewish-Americans on Sunday.

Bolton said it is too soon for the UN Security Council to impose sanctions on Iran but other countries are talking about doing so and Washington is "beefing up defensive measures to cope with the Iranian nuclear threat."

"The longer we wait to confront the threat Iran poses, the harder and more intractable it will become to solve," Bolton warned.

"The Iran regime must be made aware that if it continues down the path of international isolation, there will be tangible and painful consequences," he told the annual convention of the American-Israel Public Affairs Committee.

He said Iran poses a "comprehensive threat" as a state sponsor of terrorism as well as a nuclear aspirant and so "we must be prepared to rely on comprehensive solutions and use all the tools at our disposal to stop the threat that the Iranian regime poses."

Enrichment right

Iran claims it has the right to enrich uranium for nuclear reactor fuel as part of a peaceful energy programme; but the United States and Europe fear it will use enriched uranium to make atom bombs.

The board of governors of the watchdog International Atomic Energy Agency (IAEA) meets this week in Vienna to consider a report from the agency's chief Mohamed ElBaradei that says Iran is defying IAEA calls to halt enrichment and to cooperate fully with agency inspectors.

The issue is expected to come up on Tuesday or Wednesday.

PHOTO CAPTION

Iran's chief nuclear negotiator Ali Larijani smiles before the start of a news conference in Tehran March 5, 2006. (REUTERS)