U.S. Secretary of State Hillary Clinton is in Russia for talks on a wide range of international issues, including how to revive the Israeli-Palestinian peace process. On Thursday, she urged Russia to delay starting up the nuclear plant that it built for Iran at the port city of Bushehr.
Russia says the nuclear reactor it is building for Iran will be ready to start operations by the middle of this year.
Moscow has been helping Iran build the Bushehr facility since 1995, but work has been delayed several times.
Reporters asked Clinton about the Bushehr facility during an appearance with Russian Foreign Minister Sergei Lavrov.
"(But) we have consistently said that Iran is entitled to civil nuclear power. It is a nuclear weapons program that it is not entitled to. And if it reassures the world, or if its behavior has changed because of international sanctions, then they can pursue peaceful civil nuclear power. In the absence of those reassurances, we think it would be premature to go forward with any project at this time, because we want to send an unequivocal message to the Iranians," she said.
The U.S. and other western powers say Iran is pursuing nuclear technology in order to produce nuclear weapons. Iran insists its nuclear operations are for peaceful purposes.
Lavrov insisted the Bushehr facility eventually will open. "The project will be finished. All of the technical issues related to Bushehr are reaching their final stages and this plant will open and produce electricity," he said.
Russia has denied previous delays at Bushehr were related to ongoing concerns about Iran's nuclear program.
Moscow says the plant will come under the supervision of the International Atomic Energy Agency, and that Iran must return all used fuel rods to Moscow.
Earlier this month, Russian President Dmitri Medvedev said his country is ready to consider new sanctions against Iran, if Tehran refuses to stop enriching uranium.
On another matter, both Clinton and Lavrov indicated negotiators are close to finalizing a new treaty to cut the nuclear arsenals of the their two countries.
The U.S. and Russia have been working for almost a year on a replacement for the 1991 Strategic Arms Reduction Treaty, or START. It expired last December.