Reuters - Three top European Union powers were expected to formally call off moribund nuclear talks with Iran and to advocate sending the dispute to the Security Council when they meet on Thursday, a diplomat from one of the EU trio said.

The foreign ministers of Germany, France and Britain, along with EU foreign policy chief Javier Solana, were due to meet at 3:30 p.m. (1430 GMT) in Berlin to discuss the crisis caused by Iran's move to reactivate a nuclear fuel program mothballed under a November 2004 deal with the European negotiators.

"Everybody agrees the point of no return has been reached," the EU3 diplomat said, referring to what he said was an informal consensus reached among the bloc's 25 member states.

European diplomats say they now expect the International Atomic Energy Agency's board of governors to convene in early February to discuss referring Iran to the Security Council.

They say a clear simple majority on the IAEA's 35-nation board favours such a move, but add that EU and U.S. officials will work to achieve as much consensus as possible.

Russia and China, which have major energy interests in Iran, have previously opposed moving the dispute to the Security Council, where they both wield veto powers.

However, Iran's latest action appears to have disconcerted Moscow. Russian Foreign Minister Sergei Lavrov discussed the row with U.S. Secretary of State Condoleezza Rice by telephone.

"Both sides...expressed deep disappointment about Tehran's decision to abandon the moratorium," a Russian foreign ministry statement said.

The Security Council's five permanent members, including Russia and China, recently sent letters to Iran urging it not to restart its nuclear fuel activities.

Crude oil prices rose more than a dollar on Wednesday as dealers worried the dispute over Iran's nuclear program could lead to a disruption in supply from the world's fourth largest oil exporter.

Any embargo on Iranian oil exports would be a double-edged sword -- Iran is the world's fourth biggest crude oil exporter.

The United States already has a full embargo against Iran, but the EU could introduce more sweeping trade restrictions.

The Security Council could impose sanctions ranging from travel curbs on government officials to a full trade embargo such as those previously imposed on Libya and Iraq.