Russia says it still opposes sanctions against Iran for its nuclear program, as senior diplomats from six countries began talks in Moscow. Russia has long been trying to convince Iran to halt its uranium-enrichment program.
Russia has reiterated its opposition to imposing sanctions against Iran, and insists that diplomacy is the only way to end the stand-off over its nuclear program.
Russia will host two days of meetings of senior diplomats from the United States, China, and the G-8 countries for talks on Iran as well as other issues.
The United States and Britain say they will insist on tougher measures, including possible sanctions, if Iran fails to comply with the April 28 U.N. Security Council deadline to halt its uranium enrichment.
Last week, Iran announced it had successfully enriched uranium for the first time, and plans to press ahead with a program it says is only for peaceful purposes.
Russia has long tried to play a mediating role in the crisis, and has strongly criticized Iran recently as it continues to defy the world community.
Russia is Iran's major supplier of nuclear-power technology, and has always opposed sanctions or the use of force.
President Bush has dismissed reports of plans to use force, but says "all options remain on the table" and that the world cannot allow Iran to gain nuclear-weapons capability.
In an interview on Russian radio, Iran's ambassador to Russia, Gholamreza Ansari, said Tehran is ready to respond if a war should start. He said one way to help prevent war is to be prepared for it, although he adds that Iran does want to resolve the nuclear dispute through negotiations.
China has sided with Russia in opposing punitive measures against Iran. Chinese news agencies say its top nonproliferation official visited Tehran last weekend to ask Iranian leaders to agree to a negotiated settlement to the dispute.
But Iranian President Mahmoud Ahmadinejad remained defiant, saying that Iran would "cut the hand of any aggressor" that may attack his country.
He was speaking in Tehran at a military parade marking the Army Day holiday, in which the military showed off new weapons including missiles.