Jailed Russian businessman and Kremlin critic Mikhail Khodorkovsky failed on Tuesday in multiple legal challenges against the terms of a pending trial that his supporters say is politically motivated.
A court in Moscow will begin hearings on March 31 that could see Khodorkovsky jailed for another 22 years if convicted of embezzling $25 billion from his own oil company.
Defence lawyers argued that Khodorkovsky and his business partner, Platon Lebedev, -- both already serving eight year prison sentences for fraud and tax evasion -- are political prisoners and that the new charges are absurd and should be rejected.
Earlier the court declined the defence's request to change the state prosecutors and judge because of alleged bias.
The trial of Khodorkovsky and Lebedev will be open to journalists, said a court spokeswoman.
"The charges against Mikhail Borisovich Khodorkovsky and Platon Borisovich Lebedev remain unchanged," the judge, Viktor Danilkin, said at the end of the pre-trial hearing to review the exact charges they will face.
Once one of the richest businessmen in Russia through his Yukos oil firm, Khodorkovsky fell from favour under former President Vladimir Putin.
This latest hearings are being watched closely for any signs of a milder tone under Putin's successor, Dmitry Medvedev who has promised to improve rule of law in Russia.
In 2005, a court sentenced Khodorkovsky to eight years in prison for fraud and tax evasion.
(Reporting by Aidar Buribayev, writing by James Kilner; Editing by Richard Balmforth)