"The EU-3 informed the other participants of their intention to call for an extraordinary IAEA (International Atomic Energy Agency) board of governors meeting on the 2nd and 3rd of February," a foreign office spokesman told AFP on Monday.
Reuters reports that European powers have also began drafting a resolution to have Iran referred to the UN Security Council next month over its nuclear work, diplomats said, after Russia and the West came close to an agreement on dealing with Tehran.
Iran's resumption of nuclear research has sparked a flurry of Western diplomacy in pursuit of an IAEA vote that could result in UN sanctions being imposed on the country.
American and EU officials say Iran has failed to prove that its programme to develop fuel for civilian atomic energy is not being used as a cover for producing nuclear weapons.
Diplomats said the meeting in London on Monday of permanent council members Britain, France, Russia, China and the US, along with Germany, sought to bridge differences over Iran to enable an emergency IAEA board meeting and vote.
After Russia said it was "very close" to Western views on Iran, which favour diplomatic action to curb its atomic project, Germany, France and Britain began drafting a referral resolution to submit to the IAEA's 35-nation board, an EU diplomat said.
"It's short. It calls for [Mohamed] ElBaradei [the IAEA director-general] to report Iran to the Security Council," the diplomat said, asking for anonymity because of the subject's sensitivity.
Ahmadinejad, Iran's president,
has cultivated a tough image
Moscow, with a $1 billion stake building Iran's first atomic reactor, and Beijing, reliant on Iranian oil imports, have so far thwarted such a step by the IAEA board of governors.
But Javier Solana, the EU foreign policy chief, said on Monday he was confident that China and Russia would back the EU in sending the issue to the Security Council.
Vladimir Putin, the Russian president, signalled a change when he said after talks with Angela Merkel, the German chancellor, in Moscow: "As for Russia, and Germany and our European partners and the United States, we have very close positions on the Iranian problem."
However, Putin also said the crisis should be solved "without abrupt, erroneous steps" - a possible nod to concerns of some that a rapid push towards UN sanctions could backfire.
"We must move very carefully in this area," he said.
There was no immediate comment from China. Beijing said last week that resorting to the Security Council might "complicate the issue", citing Iran's threat to hit back by halting snap UN inspections of its atomic plants.
ElBaradei: Tehran may be just
months from having a weapon
Diplomats said China's resistance would be harder to overcome,
although Beijing's decision to join other permanent council members in formally protesting against Iran's move showed that the Chinese shared Western concerns.
Iran says it seeks atomic energy only to power its economy - the IAEA has found no proof to the contrary - within its rights as a signatory to the nuclear Non-Proliferation Treaty.
But Tehran's concealment of nuclear activities for almost 20 years until it was exposed by dissident exiles in 2002, a patchy record of co-operation with the IAEA since, and calls for wiping out Israel have fired Western resolve to rein in the Iranians.
ElBaradei told Newsweek magazine that it was not impossible
Iran had a secret nuclear arms programme.
"If they have the nuclear material and they have a parallel weaponisation programme along the way, they are really not very far - a few months - from a weapon," he said.
Many Iranians favour acquiring a full nuclear fuel industry to be taken seriously as a Middle East power and deter what they see as threats of US and Israeli attack.
Washington calls Iran a major orchestrator of terrorism, something Tehran denies.
Diplomats said the resolution drafting was at an early stage, and the EU was consulting all IAEA board members to obtain as much unanimity as possible if it came to a vote.
Iran, the world's fourth-largest exporter of crude oil, has said that any attempt to isolate it could drive up world energy prices, damaging industrialised economies.