US Secretary of State Condoleezza Rice joined European powers tonight and said Iran must be referred to the UN Security Council over its nuclear plans.
Iran's President Mahmoud Ahmadinejad
Ms Rice also said the United States wanted an emergency meeting of the International Atomic Energy Agency, or IAEA, board of governors to discuss Iran's defiant resumption of uranium enrichment work.
"That meeting would be to report Iran's noncompliance with its safeguards' obligations to the UN Security Council," Ms Rice told a news conference.
Earlier, France, Germany and Britain, the three European partners negotiating with Iran, said talks with Tehran had reached an impasse and they also agreed it should be sent to the UN Security Council for possible sanctions.
The so-called EU3 and the United States believe Iran is developing nuclear weapons under cover of a civilian atomic energy program.
Iran denies the charge, insisting its nuclear ambitions are limited to peaceful power generation.
Iran escalated its nuclear standoff with the West earlier this week when it began removing UN seals on equipment used to enrich uranium - a process of purifying it for use as fuel in nuclear power plants or, when very highly enriched, in bombs.
Ms Rice said the removal of seals demonstrated that Iran had chosen confrontation with the international community over cooperation and negotiations.
"These provocative actions by the Iranian regime have shattered the basis for negotiations," she said.
But UN Secretary-General Kofi Annan said Iran remained interested in "serious and constructive negotiations" with the European Union on its nuclear program, as long as the talks don't go on too long.
Mr Annan said after a 40-minute telephone conversation with Iran's chief nuclear negotiator, Ali Larijani, that Tehran was "interested in serious and constructive negotiations, but within a time frame".
EU3 officials are set to meet their counterparts from China, Russia and the United States in London next week to discuss how to deal with Iran's disputed nuclear program.
Iran intensified the standoff over its nuclear plans when it began removing UN seals at uranium enrichment research facilities on Tuesday and announced it would soon resume "research and development" on producing enriched uranium.
But after today finishing the process of removing all the seals placed by the IAEA on its nuclear fuel research sites, a source said it would be some time before uranium enrichment could begin.
"It's probably going to have to rebuild the entire [cascade of enrichment centrifuges]. There's a lot of humidity, corrosion. It's going to take a long time," the source close to the IAEA said.
Iran removed seals at three sites - Natanz, Pars Trash and Farayand Technique. Iran has installed 164 centrifuges - machines that enrich uranium by spinning at supersonic speeds - at Natanz.