World powers are expected to meet Thursday in Berlin to discuss their next move involving Iran's controversial nuclear program.
Diplomats from the U.S., France, Britain, China and Russia and Germany will gather for the talks.
The United States has said it expects all Security Council members to abide by their decision to sanction Iran for disregarding an August 31 U.N. deadline to stop enriching uranium.
Russia and China have been reluctant to punish Iran.
Also Thursday, Iran's top nuclear negotiator, Ali Larijani, is due to meet EU foreign policy chief Javier Solana in Madrid. The two had been expected to meet Wednesday in Vienna, but Iran postponed the talks. Iranian state media also report Larijani will speak with other European officials while in Madrid.
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 the charge.
Russia's foreign minister said Wednesday any sanctions against Iran must rule out the use of military force. He also repeated that Russia prefers resolving the standoff through negotiations.
Some information for this report was provided by AFP, AP and Reuters.