Iran has not confirmed charges made Thursday by Washington's top arms control official, John Bolton, that it had told the trio of its plans and that this was a direct violation of Iranian pledges to the International Atomic Energy Agency.

The foreign ministry has said only that Hassan Rowhani, head of Iran's Supreme National Security Council and top nuclear negotiator, had sent a letter to the trio's foreign ministers and to IAEA chief Mohamed ElBaradei that "outlined Iran's point of view on nuclear technology and its use."

But Berlin, London and Paris confirmed Bolton's charges on Friday, and said they were preparing a joint response to Iran's announcement it was breaking a deal with them over the centrifuges.

All expressed disappointment at the letter sent to them, in a move Bolton described as proof of the Islamic republic's intent to work on a secret nuclear weapons programme.

"We are disappointed at the Iranian decision," a Foreign Office spokesman in London told AFP, adding: "We don't understand why they've taken this decision."

A German spokesman said: "The foreign ministry in Berlin regrets the announcement made by the Iranian authorities."

And a diplomatic source in Paris said France had received the letter and was consulting the other two states on how to respond to the violation of their deal.

"We are working together with the British and the Germans toward a common and coordinated position on the matter," the French source said.

Bolton, hawkish undersecretary of state for arms control and security, said Washington had always suspected that the Iranians had not completely stopped centrifuge production.

"They have not, at least at this point, said that they would resume actual enrichment activities, but it seems to me perfectly obvious that Iran is not producing components for uranium centrifuges to use them as knickknacks in Iranian living rooms," Bolton said.

"This is an act of defiance of the IAEA Board of Governors, it is a thumb in the eye of the international community," he said.

"It has been our view, it remains our view (and) Iran's action today confirms our view that its nuclear weapons programme is a threat to international peace and security and should be referred to the UN Security Council," Bolton said.