Russian prosecutors have filed new charges of money-laundering and embezzlement against the jailed oil tycoon Mikhail Khodorkovsky.
Khodorkovsky says his case is politically motivated
His lawyer said the same charges were filed against the ex-Yukos chairman's business partner Platon Lebedev.
The pair, jailed in 2005, are serving an eight-year term for fraud and tax evasion in the Chita region of Siberia, where the new charges were filed.
Khodorkovsky was once one of Russia's most powerful men.
He built up a multi-billion-dollar fortune before falling foul of the authorities. He was arrested in 2003 along with Platon Lebedev.
Khodorkovsky and Lebedev were facing the possibility of release in 2008 or 2009 - but that appears unlikely now.
Khodorkovsky's lawyer Yuri Shmidt described the latest charges as "absurd, even crazy".
Russian media say the charges allege that up to $25bn was embezzled.
"The sums mentioned are crazy - quite simply it would be impossible to steal, launder or in some other way conceal them," Mr Shmidt said, in a statement posted on Khodorkovsky's website.
Russian critics accused Khodorkovsky of exploiting the country's natural wealth for personal gain.
His supporters say the case against him was politically motivated and he is paying the price for his political ambitions.