MOSCOW (Reuters) - A Russian court has refused to consider a parole request from jailed oil tycoon Mikhail Khodorkovsky because lawyers did not supply the proper documents showing he is in prison, Kommersant newspaper said on Tuesday.
Khodorkovsky, once Russia's richest man, was jailed in 2003 after falling foul of the Kremlin under then-President Vladimir Putin and filed for parole last month. He is serving a 13-year sentence and is due to be released in 2016.
A spokeswoman for Moscow's Preobrazhensky court was quoted by Kommersant as saying Khodorkovsky's lawyers had not supplied appropriate documents showing the tycoon was serving a jail term and the application had been returned to them.
The spokeswoman could not be reached for immediate comment.
President Dmitry Medvedev said last month it would not be dangerous to release Khodorkovsky, but Prime Minister Putin has taken a tougher stance, comparing the tycoon to American gangster Al Capone.
Putin has called Khodorkovsky as thief who should remain in jail.
Khodorkovsky has said repeatedly his convictions for fraud, theft and money-laundering were ordered by senior officials who wanted to carve up his oil company and take revenge for a perceived challenge to Putin's authority.
Khodorkovsky built a fortune by buying state assets cheaply following the collapse of the Soviet Union in 1991, but his business empire -- which produced more oil than OPEC member Qatar -- was split up and sold after his arrest in 2003.
Russian state-controlled oil firm Rosneft eventually bought the largest production assets, including Yuganskneftegaz, making Rosneft Russia's biggest oil producer.
Khodorkovsky and his business partner Platon Lebedev were sentenced to stay in jail until 2017 in a second trial in December, but the sentence was reduced by one year on appeal.
Lawyers for the two men said they had filed an official compliant, asking prosecutors to open a criminal case against trial judge Viktor Danilkin after his aide said the verdict was dictated by to him by higher judges.
State news agency RIA said prosecutors had informed the lawyers that an investigation had been started on the basis of the complaint.
Reporting by Guy Faulconbridge, editing by Jon Boyle