By VLADIMIR ISACHENKOV, Associated Press Writer

MOSCOW - Russia will ship fuel for a nuclear reactor it's building in southern Iran even if Tehran does not agree to stricter United Nations  monitoring, the Russian Foreign Ministry said Thursday.

Foreign Ministry spokesman Alexander Yakovenko said it was "actively pushing" for Iran to sign an additional protocol with the International Atomic Energy Agency that would grant the U.N. nuclear watchdog broader access to Iran's nuclear sites and information.

But Iran has no legal obligation to accept stricter controls and its failure to do so won't hinder its $800 million contract with Russia for a light-water reactor in the southern port of Bushehr, Yakovenko said.

"The protocol is an agreement that is signed on a voluntary basis," Yakovenko told reporters.

Moscow would require Iran to sign an agreement to ship spent nuclear fuel back to Russia, the spokesman said.

Plutonium, which can be used in nuclear weapons, can be derived from reprocessing spent fuel from reactors.

Iran's ambassador to Moscow, Gholamreza Shafei, told a news conference that Russia had given assurances that the Bushehr contract would remain in force.

Shafei said Iran would sign the agreement to ship the spent nuclear fuel to Russia as a sign of goodwill between the two nations.

The statements apparently contradict British Prime Minister Tony Blair  , who said Wednesday that Russian President Vladimir Putin had pledged not to supply any nuclear fuel to Iran until the government in Tehran agrees to closer IAEA supervision of its nuclear program.

Iran's burgeoning nuclear program has been one of the major sources of friction in U.S.-Russian relations since 1995, when Moscow signed the Bushehr contract. The United States is concerned the deal could help Tehran build an atomic bomb.

Russia recently indicated that it shares U.S. concerns about the Iranian nuclear program. Speaking Tuesday after the Group of Eight summit in France, Putin said Moscow would insist that all Iranian nuclear programs be put under IAEA control.

At the same time, Putin defended Russia's right to cooperate with Iran and warned against what he called pressure resulting from "unfair competition."

Yakovenko said Thursday that Moscow would supply uranium fuel for the Russian-built reactor in Bushehr only after Iran signs an agreement to ship the spent nuclear fuel back to Russia.

Russian Atomic Energy Minister Alexander Rumyantsev said earlier this week that Iran was ready to sign the document. He said the delay so far in signing was purely technical and was explained by the need to coordinate with Russian government agencies.

Rumyantsev also said that the Bushehr reactor is now set to begin operating in 2005, not next year as originally planned because of the need to replace some equipment provided by Germany's Siemens AG  before it abandoned the project following Iran's 1979 Islamic Revolution.

Iranian officials, however, have said they expect the reactor to come on line later this year.

The delay announced by Rumyantsev might indicate that Moscow is heeding U.S. appeals to slow down the contract until Iran proves it isn't covertly building nuclear weapons.