A senior Iranian official says his government is postponing nuclear talks with the European Union that were expected to begin Wednesday.
Iran's chief nuclear negotiator, Ali Larijani, and the EU's foreign-policy chief, Javier Solana, had been expected to meet in Vienna.
But, Ali Ashgar Soltaneih, Tehran's representative at the International Atomic Energy Agency said the meeting was postponed because of "a procedural matter."
The United States has said it expects all U.N. Security Council members to abide by their decision to sanction Iran for disregarding the August 31 deadline to stop uranium enrichment.
In the past, Russia and China have been reluctant to punish Iran. Wednesday Russian Foreign Minister Sergei Lavrov said any sanctions against Iran must rule out the use of military force.
Speaking in South Africa, Mr. Lavrov repeated Russia's position that it prefers resolving the standoff through negotiations.
The United States, Russia, France, Britain and China - the Security Council's permanent members - are expected to meet with German officials on Thursday in Berlin to discuss their next move.
Iran says it is ready for negotiations, but will not halt uranium enrichment - a process the United States and its allies say is aimed at developing nuclear weapons. Iran denies this.
In a speech in Washington Tuesday President Bush said the world's free nations will not allow Iran to develop a nuclear weapon.
Some information for this report was provided by AFP, AP and Reuters.