The jailed former chairman of the Yukos oil company has appealed his fraud conviction to the European Court of Human Rights in Strasbourg.
An attorney for Mikhail Khodorkovsky gave no details of what was in the complaint filed Tuesday, however, Russian news reports say it alleges the former oil tycoon did not get a fair trial.
Reports also say the lawyer also formally complained that prison authorities placed Khodorkovsky in solitary confinement last week for drinking a cup of tea outside a designated eating place.
Khodorkovsky was sentenced to eight years in a Siberian prison camp last year for tax evasion and fraud.
His supporters say the sentence was politically motivated because of Khodorkovsky's backing of opposition candidates.
Khodorkovsky's former business partner, Planton Lebedev, has also appealed his conviction to the Strasbourg court.Some information for this report was provided by Reuters.