An executive recently assigned to saving Yukos, Russia's former biggest oil producer, from bankruptcy has been arrested on charges of embezzlement and money-laundering, prosecutors said Thursday.

Vasily Aleksanian was being interrogated by prosecutors, a spokeswoman for the general prosecutor's office said. Charges officially were filed against him, his lawyer, Gevorg Davgyan, said later Thursday, according to the RIA Novosti news agency.

Earlier, the Simonovsky court had ruled that prosecutors could launch criminal proceedings against Aleksanian, who was appointed vice president at Yukos last week after heading its legal department. Russian law requires that prosecutors receive court permission to file charges against a former lawyer.

A spokeswoman for the general prosecutors office said Aleksanian had been detained as a suspect and was being interrogated by prosecutors.

Yukos spokeswoman Claire Davidson said that Aleksanian's Moscow lawyer had called his client Thursday and learned that he was being arrested.

"I'm without words to describe it," Davidson said. "He was working specifically to protect all shareholders (in Yukos)."

Yukos has been crippled by billions of dollars in back-tax bills that are widely seen as political retribution, and has been put under external supervision before bankruptcy hearings on June 27.

A consortium of Western banks sought to have Yukos declared bankrupt after it defaulted on nearly half of a $1 billion syndicated loan arranged three years ago by Societe Generale SA with Deutsche Bank AG, Citigroup Inc. and HSBC PLC.

The bankruptcy hearings are likely to be the closing chapters on Yukos, which was built up by billionaire Mikhail Khodorkovsky to become Russia's biggest oil producer before his arrest and conviction and the company's dismantlement and nationalization.

State oil firm Rosneft already owns Yukos' former main production unit and is believed to be eyeing the company's remaining 600,000 barrels per day of production capacity and a major refinery. Its hand has been strengthened by an agreement to purchase the debt from the Western banks.

Khodorkovsky is serving an eight-year sentence for fraud and tax evasion in a Siberian prison camp. Observers say the criminal case against him, and the related back tax case against the company, were punishment for his political ambitions and a step to reassert state influence over Russia's strategically important oil sector.

A web of investigations and lawsuits have been launched against other employees of the fallen oil company. This month, senior company lawyer Svetlana Bakhmina is due to be sentenced on embezzlement charges. Prosecutors have called for nine years imprisonment.

Most of the oil company's senior managers have fled Russia and are working from London.

Separately, a Moscow court on Thursday rejected Khodorkovsky's appeal against being sent to serve his time in a Siberian prison camp, six time zones from Moscow on the Chinese border. Khodorkovsky's lawyers had argued that he should be imprisoned in Moscow or the Moscow region where he is registered and resided before his arrest.