Prosecutors filed new money laundering charges Monday against jailed Russian oil tycoon Mikhail Khodorkovsky and his business partner Platon Lebedev, Russian news agencies reported, citing their lawyers.

The Interfax news agency quoted lawyer Karina Moskalenko as saying that prosecutors in the Siberian city of Chita had indicted Khodorkovsky on charges of money laundering.

The ITAR-Tass and Interfax news agencies earlier quoted Lebedev's lawyer, Konstantin Ribkin, as saying that prosecutors had charged his client on the same count.

Khodorkovsky, founder of the now bankrupt oil giant OAO Yukos, has been serving an eight-year sentence after being convicted in 2004 on fraud and tax evasion charges following a politically charged trial. Lebedev also is serving eight years on these charges.

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Prior to his arrest and the parallel tax probe that saw most of his oil empire transferred to a state company, Khodorkovsky was estimated by Forbes magazine to have a fortune worth $15 billion.

The case was widely seen as a Kremlin-driven vendetta after Khodorkovsky funded opposition parties, and a means for the state to regain control of a chunk of the strategically important oil sector.

Khodorkovsky could face up to 15 years if convicted on the money laundering charges. He has been in detention since October 2003 and could be eligible for parole later this year.

Kremlin critics suggested the new charges were aimed at ensuring he remains in prison and presents no political threat.

Prison terms on separate charges are not usually served consecutively in Russia; convicts are jailed for the longest sentence.