Adamov "is ready to prove his innocence both in Russia and America," Timofei Gridnyov was quoted by Interfax news agency as saying, but added that this would be possible "only if the US government provides guarantees of his security."

On Thursday, Switzerland's Federal Tribunal ruled in favour of handing Adamov back to Russia, where he stands accused of skimming 17 million dollars (14.4 million euros) from state coffers while he was atomic energy minister between 1998 and 2001.

Washington expressed disappointment at the Swiss court's ruling as it too wants to try Adamov on charges of fraud and money laundering in connection with nine million dollars sent by the US government to help Russia improve its nuclear safety after the break-up of the Soviet Union.

"He is ready to provide evidence proving that everything he did during the years of Russia's economic collapse was exclusively aimed at reviving" the NIKIET nuclear design and research institute that he used to direct, Gridnyov said.

Russian officials have said they are concerned Adamov could reveal state secrets if sent to the United States and said they were "satisfied" by the court's decision.

Adamov, 66, has been in jail in Switzerland since he was arrested in the capital Bern on May 2 at the request of US authorities.