Manouchehr Mottaki, the Iranian foreign minister, was quoted by the official IRNA news agency as saying on Friday that his "government will be obliged to end all of its voluntary measures if sent to the UN council".

The United States and the European Union's three biggest powers said on Thursday talks with Iran to curb its nuclear programme were at an impasse and Tehran should be brought before the Security Council.

Accusing Iran of turning its back on the international community, the EU's big three, Britain, Germany and France, said it had consistently breached its commitments and failed to show the world that its nuclear activities were peaceful.

Frank-Walter Steinmeier, the foreign minister of Germany, said: "Our talks with Iran have reached a dead end."

His statement followed talks in Berlin with his British and French counterparts and Javier Solana, the European Union foreign policy chief.
   
A joint statement from the so-called "EU3" countries said: "We believe the time has now come for the Security Council to become involved."

Condoleezza Rice, the US secretary of state, joined calls for an emergency meeting of the board of governors of the International Atomic Energy Agency (IAEA), the UN nuclear watchdog, to seek a referral to the council, which can impose sanctions.