US Secretary of State Condoleezza Rice has urged the UN to confront Iran's "defiance" over its nuclear programme.
Earlier, foreign ministers from the UK, France and Germany said the time had come for Iran's nuclear issue to be dealt with by the UN Security Council.
Iran says it will end all voluntary co-operation over its nuclear policy, if it is referred to the Council.
Russia did not rule out referring Iran to the UN, but said not all diplomatic steps had been taken.
The UK, France and Germany - the so-called EU three - met in Berlin on Thursday in response to Iran's decision to resume nuclear research this week.
Speaking afterwards, they said talks with Iran had reached a "dead end" and called for an emergency session of the UN's nuclear watchdog, which could refer Iran to the council and lead to possible sanctions.
Ms Rice backed the EU move, saying: "These provocative actions by the Iranian regime have shattered the basis for negotiation."
Speaking to reporters in Washington, she said Tehran had deliberately escalated the situation and was "in dangerous defiance of the entire international community".
IRAN'S NUCLEAR STANDOFF
Sept 2002: Work begins on Iran's first reactor at Bushehr
Dec 2002: Satellites reveal Arak and Natanz sites triggering IAEA inspections
Nov 2003: Iran suspends uranium enrichment and allows tougher inspections
June 2004: IAEA rebukes Iran for not fully co-operating
Nov 2004: Iran suspends enrichment under deal with EU
Aug 2005: Iran rejects EU plan and re-opens Isfahan plant
Jan 2006: Iran re-opens Natanz facility
Ms Rice talked of "a menu of possibilities" for diplomatic action against Iran.
But she said the US did not "at this point" have on its agenda the option of military action.
The BBC's Justin Webb in Washington says her words show the White House is well aware that the coming diplomatic showdown with Iran cannot be managed alone.
Mr Bush is to meet the new German Chancellor Angela Merkel on Friday in an attempt to improve relations and win German support for a tough line against Tehran, our correspondent adds.
The US and members of the EU have accused Iran of covertly seeking to develop nuclear weapons. Tehran insists its nuclear programme is for peaceful purposes only.
UN Secretary General Kofi Annan told the BBC that Iran's chief nuclear negotiator, Ali Larijani, had told him Iran remained "interested in serious and constructive negotiations, but within a time-frame".
Mr Annan said he was keen for the issue to be resolved through the IAEA if possible.
Top Japanese officials said there would be no option but to refer Iran to the Security Council unless it "changes its behaviour" over its nuclear activities.
Foreign Minister Manuchehr Mottaki said Iran would end snap UN checks of its atomic facilities and would resume uranium enrichment if its case was sent to the Security Council.
"The government will be obliged to end all of its voluntary measures if sent to the UN council," Mr Mottaki was quoted as saying by the official IRNA news agency.
The crisis over Iran's nuclear programme intensified this week after Iran removed seals at three nuclear facilities, including a uranium enrichment plant at Natanz, following a two-year freeze.
Since last August, Iran has resumed all nuclear activity apart from enrichment, which can produce fuel for power stations or, under certain conditions, for bombs.