UK police have arrested the Russian tycoon Boris Berezovsky for alleged fraud at the request of the Russian authorities.
Boris Berezovsky denies fraud
The Metropolitan Police said officers arrested Berezovsky in London early on Monday.
A Russian extradition request charges that Mr Berezovsky defrauded the administration of the Samara region of billions of roubles as director of the LogoVaz company in the mid-1990s.
Russia requested his extradition in November.
Mr Berezovsky told BBC News Online at the time he was absolutely confident that he could prove in a British court that he had no case to answer in Russia.
A LogoVaz associate, Yuli Dubov, was also arrested on Monday, police said.
Both men have been bailed to appear at Bow Street Magistrates Court on 2 April.
Mr Berezovsky, one of the richest men in Russia, was a member of former President Boris Yeltsin's inner circle.
The charge alleges that between 1/1/94 and 31/12/95 they defrauded the Administration of Samara Region of 60 billion roubles
He was one of a group of businessmen termed "oligarchs" at the time, because of their considerable political influence.
He fled to London after a corruption inquiry was launched against him in Russia five years ago.
Mr Berezovsky still has major interests in the car industry, oil and the media.
He first set up LogoVaz as a car dealership in the Samara region in the late 1980s, going into partnership with Russia's largest car manufacturer, Avtovaz.
He has denied the corruption charges and told BBC News Online last week that he believed he could succeed in getting Russian authorities to drop the warrant for his arrest.
He has set up a centre-right political party, and said he wanted to return to Russia to take part in December's general election.
The UK and Russia have formal extradition procedures, agreed in 2001 after the lapse of a 19th Century treaty.