A judge on Thursday upheld a decision to keep Russian oil tycoon Mikhail Khodorkovsky behind bars until March 25, rejecting an appeal for him to be placed under house arrest.

One of Khodorkovsky's lawyers, Karinna Moskalenko, said the court's decision had been "predetermined" and said she planned to appeal to the European Court of Human Rights. Khodorkovsky has been in pretrial detention since his Oct. 25 arrest on charges including fraud and tax evasion. The charges are widely seen as Kremlin punishment for the billionaire's growing financial clout and support for opposition parties. The Moscow City Court decision on Thursday upheld last month's ruling to keep the former head of Yukos oil company in jail. Defense lawyer Genrikh Padva also said the lower court ruling should be overturned because it was made during a closed hearing. The three-judge panel granted a defense request to open Thursday's hearing. President Vladimir Putin (news - web sites), who has denied any political motivation behind the prosecution of Khodorkovsky and has cast it as part of a legitimate effort by law enforcement authorities to tackle Russia's economic crime and corruption, has said the magnate's trial should be open. The court decisions will keep Khodorkovsky in jail until after the March 14 presidential election, which Putin is expected to win easily. Khodorkovsky watched attentively through a video link between the courtroom and Moscow's Matrosskaya Tishina jail. Addressing the courtroom, Khodorkovsky maintained his innocence, calling the accusations against him unfounded and his detention illegal. He said he had made no attempts to avoid prosecutors or flee the country before his arrest, which came amid a wide-ranging probe into Yukos that had already seen the jailing of another key shareholder. At one point before his arrest, Khodorkovsky even publicly declared that he would face jail rather than become a forced exile. Appearing near tears, Khodorkovsky said he could not betray the "tens of thousands" of Yukos employees he said had offered financial guarantees that he would not evade the prosecution if freed from jail. The magnate, who quit as Yukos chief executive shortly after his arrest, also said that he would no longer be able to commit economic crimes if he is freed. He denied prosecutors' claims that he has tried to influence witnesses or hinder the investigation.