"Russia is willing to cooperate further with Iran, including in the nuclear field, in strict respect of international obligations," Russian Foreign Minister Igor Ivanov said in a statement.
The top Russian diplomat said that Moscow was still awaiting official notification from the UN nuclear watchdog, the International Atomic Energy Agency (IAEA), on Tehran's promise of full cooperation with the IAEA Tuesday.
But he added that Russia expected Iran to provide all information about its nuclear programme, allow tougher inspections of its nuclear sites and to halt uranium enrichment.
"All this would remove the international community's concerns about Iran's nuclear programme," Ivanov said.
On Tuesday, Iran promised the visiting foreign ministers of Britain, France and Germany that it would show "full transparency" to the UN's nuclear watchdog and allow an intrusive inspections regime as well as halt uranium enrichment.
The deal was struck just 10 days before the end of October deadline for Iran to come clean about its nuclear programme.
Russia is building Iran's first nuclear plant, Bushehr, in a deal worth about 800 million dollars.
A top Iranian official said Tuesday that Tehran would sign a deal with Moscow soon promising to return supplies of Russian nuclear fuel used in the plant in southern Iran, opening the way to completion of the project.
Under pressure from the United States and Israel, which fear that Iran is developing nuclear weapons with the project's help, Russia has so far delayed signing the agreement on the return of the spent fuel.