A senior official in Iran's national atomic energy organisation, Mohammad Saeedi, told the student news agency ISNA that Rumyantsev was scheduled to arrive here on February 25.

The announcement came after Iran agreed to sign a key deal with Russia on the return of spent fuel that will finally let Moscow launch the Islamic republic's first nuclear power plant.

The Russian-built plant at Bushehr -- whose construction had been launched by Germany in the 1970s -- was initially due to go on line last year.

But under pressure from the United States to abandon the 800 million dollar project altogether, Moscow had set the condition that all spent fuel be returned, amid fears Iran could reprocess it by upgrading it through centrifuges.

Tehran has in the past used various arguments to avoid signing the agreement. It said the material was too volatile and dangerous to transport back to Russia, and that Moscow was charging too much.

According to Saeedi, Rumyantsev's three-day visit will also include the opening of negotiations on the second phase of Bushehr, a visit to the plant itself, and the fixing of a date for it to go on stream.

The United States and Israel had launched an international campaign against Russia's Bushehr project but Moscow has countered that it will ensure the plant remains harmless to protect its own security interests.

Russian diplomats have also admitted that the Bushehr deal is playing a key role in keeping Russia's atomic energy industry afloat.

Announcement of the imminent deal came just weeks after the US administration said it could not rule out the use of force if Tehran failed to drop its nuclear ambitions.

The United States accuses Iran of using atomic energy as a cover for weapons development, a charge Tehran denies.

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