Mikhail Khodorkovsky's lawyer says his client has been sent from Moscow to a prison camp and accused authorities of holding up his request for parole.
Vadim Klyuvgant said authorities had informed Khodorkovsky's wife that he was sent to a prison camp, but did not tell her the exact location of the detention facility.
Khodorkovsky, the former head of the now dismantled Yukos oil company, and his business partner Platon Lebedev have been in prison since 2003 and were convicted of a second set of fraud charges in December.
Ahead of his second trial, Khodorkovsky had been transferred from the Siberian prison camp where he was serving his first sentence to a Moscow prison. He had requested parole on May 27 after serving half of his prison sentence.
compiled from agency reports