U.S. Secretary of State Condoleezza Rice and her counterparts from the other permanent U.N. Security Council member countries and Germany will convene in London Friday on the Iranian nuclear program. They will discuss what strategy to pursue now that efforts by the European Union to convince Iran to end uranium enrichment have apparently reached a dead-end.

The talks between E.U. chief diplomat Javier Solana and Iranian nuclear negotiator Ali Larijani had dragged on for more than a month beyond the August 31 deadline the Security Council had set for Iran to halt enrichment.

But Solana declared Wednesday that "endless hours" of talks with the Iranians had yielded little progress. The London meeting is being convened largely at the behest of the United States and Britain, who want to see an move toward sanctions against Tehran at the U.N. starting next week.

State Department Deputy Spokesman Tom Casey told reporters sanctions are the logical next step after the E.U. initiative was spurned by Tehran. "It's clear, as Mr. Solana has signaled, that the process and the discussions between him and Mr. Larijani are drawing to an end. It is clear that we don't have a positive response from the Iranians to the offer that has been made to them. So as we've always said, the next step then is to proceed with a sanctions resolution under Article 41, Chapter 7."

The provisions of the U.N. Charter cited by Spokesman Casey authorize the Security Council to impose sanctions that do not involve the use of force, such as economic and diplomatic penalties and curbs on air traffic.

U.S. diplomats have said they would like to see a layered approach of increasingly severe sanctions against Tehran, starting with an embargo on sales to Iran of nuclear or missile technology.

But others among the  "P-5 plus 1", notably Russia and China, are reluctant to move to punitive action.

Russian Foreign Minister Sergei Lavrov said in Warsaw Thursday that sanctions would be an extreme measure until all diplomatic possibilities are exhausted.

Even getting the agreement for the London ministerial meeting appeared to have been difficult.

Until confirmation of the gathering from Secretary of State Rice's traveling party in Baghdad late Thursday, officials here were citing scheduling problems, and saying the talks would probably be at the political-director level.

U.N. Security Council Resolution 1696 approved at the end of July, gave Iran until August 31 to suspend enrichment and reprocessing and return to negotiations over its nuclear program, or face sanctions.

Iran insists the enrichment work is part of an entirely peaceful nuclear energy program, but the United States and some European allies believe Tehran has long had a covert weapons project.

Iranian President Mahmoud Ahmadinejad, who has depicted uranium enrichment as a national right, said Thursday Iran would not be frightened by sanctions threats.