A former Russian atomic energy minister has been arrested in Switzerland at the request of the United States, where he is wanted for money laundering.
Adamov's laywer says the charge is "baseless"
Yevgeny Adamov, a nuclear physicist, was detained while on a visit to Bern, the Swiss justice ministry has said.
He is accused of diverting up to $9m (£4.7m) the US gave to Russia to improve security at its nuclear facilities, the Swiss added.
A lawyer for Mr Adamov has been quoted as saying the charge is "baseless".
Mr Adamov, who was minister from 1998 until 2001, is due to appear before a Swiss court to say whether he agrees to be extradited.
He reportedly travelled to Bern to discuss with Swiss authorities the freezing of some of his daughter's bank accounts.
Mr Adamov currently jointly owns a consultancy firm based in Pennsylvania.
Before serving as minister, he headed Moscow's NIKIET nuclear research institute, which developed nuclear weapons.
He has been criticised by a Russian parliamentary committee for illegally setting up companies inside Russia and abroad.
Since the fall of the Soviet Union, the US has helped Russia recover nuclear material from outdated warheads and improve safety at its nuclear reactors.