"I hope and expect that this is not the end of the 3+3 Group's efforts," he told reporters, referring to attempts by Britain, France, Germany, the United States, China and Russia to convince Iran to abandon sensitive nuclear fuel work.

"But there is no question that without such a meeting, which we urgently need in the current situation, it will be more complicated to bring the necessary international pressure to bear," Steinmeier said.

In Washington, a senior State Department official said earlier that the meeting, planned for Thursday on the sidelines of the UN General Assembly session might not take place, after Russia said it would stay away.

"We do not see any fire that requires us to toss everything aside and meet to discuss Iran's nuclear program in the middle of a packed week at the United Nations General Assembly," the Russian Foreign Ministry said in a statement Tuesday.

Moscow's statement apparently meant Russia was walking out of the meeting.

It was also an official response to US suggestions that the United States and Russia could work together in some areas but not others.

"It would be very desirable for Washington to finally decide what it wants in its relations with Moscow. If it wants to punish Russia, this is one thing. If it agrees we have common interests... that is another," the Russian foreign ministry said.

"To use the words of Condoleezza Rice, you can't have it both ways," it added, referring to a phrase that the US secretary of state has used in criticising Russia's conflict with Georgia last month.