The Security Council will then start discussing possible sanctions on Iran next week, though Russia believes it's too soon and that further efforts are needed to push Iran to negotiate, diplomats said Thursday.

To avoid alienating the Russians and the Chinese - major commercial partners of Iran - any sanctions are likely to be relatively mild, including embargoes on missile and nuclear technology, and possible travel bans and other penalties on Iranian officials involved in their country's nuclear programme.

Meanwhile, Mahmoud Ahmadinejad, the Iranian president, reiterated on Thursday that his country would not be frightened by threats to impose sanctions.

"Those who threaten Iran by sanctions and embargo should know that this nation lived under the hardest situation in the past 27 years and achieved nuclear technology. This nation will not be frightened by the threats," state-run television quoted Ahmadinejad as saying.

Iran insists that its enrichment of uranium is purely for peaceful purposes to be used for nuclear energy. But the US and many European nations believe Iran wants to enrich uranium to produce nuclear weapons.

Participants

Condoleezza Rice, the US secretary of state; Margaret Beckett, the British foreign secretary; and Philippe Douste-Blazy, the French foreign minister, were to attend the London meeting on Friday, their offices said.

Germany, Russia and China will also send high-level officials to the talks, scheduled for 1600 GMT at Lancaster House, Beckett's official central London residence, the spokesman said, but he did not know whether they would be foreign ministers.

The representatives are likely to confirm that the European-Iranian talks are at a standstill and issue a statement referring the Iran file back to the Security Council and stating the principles they agree on, a senior council diplomat said, speaking on condition of anonymity because talks are still taking place.

Lower-level officials from the six nations will meet in London before the ministers arrive, the Foreign Office said.

Conflicting reports

Britain announced the planned talks after hours of conflicting reports about whether the ministers planned to meet, suggesting jostling among diplomats behind the scenes.

Rice, who was visiting Baghdad, said earlier on Thursday that the six countries' foreign ministers might have to arrange a conference call rather than gathering in person.

Talks between European and Iranian negotiators have failed to convince Tehran to suspend its enrichment programme.

Emyr Jones Parry, Britain's UN ambassador, said he expects "the Iran dossier" to return to the council "in the course of next week".

He said Britain "will be discussing with its partners and with members of the council the basis for action by the council to adopt measures under Article 41 against Iran".

Economic penalties

Article 41 authorises the Security Council to impose sanctions that do not involve the use of armed forces, such as economic penalties, breaking diplomatic relations or banning air travel.

The council gave Iran until August 31 to suspend enrichment in return for a package of incentives or face punishments under Article 41, but the council has held off any action because of talks between European foreign policy chief Javier Solana and Iran's top negotiator Ali Larijani.

Solana conceded on Wednesday that "endless hours" of talks with Larijani had made little progress and suggested the dispute could wind up at the UN soon. But he stressed on Thursday that dialogue with Iran must continue even if nuclear talks fail.

Sergey Lavrov, Russia's foreign minister, said Moscow remains opposed to sanctions against Iran for now.

Diplomatic possibilities

"I think that until all diplomatic possibilities have been exhausted, sanctions would be extreme," Lavrov said in Warsaw after meeting with his Polish counterpart.

"I think we need to do all we can to push Iran towards starting negotiations."

Later, he accused the US of "complicating" the six-nation talks with Iran.

Lavrov did not elaborate, but he was apparently referring to legislation signed by US President George Bush on September 30 toughening unilateral sanctions on Tehran.

The new law imposes mandatory sanctions on entities that provide goods or services for Iran's weapons programme.