Jailed Russian oligarch Mikhail Khodorkovsky has said he will never admit he is guilty of the crimes he was convicted of, even if offered early parole.

Khodorkovsky, who has been convicted in two separate trials since his arrest in 2003, denies the charges against him. He claims his imprisonment over alleged tax evasion and money laundering is politically motivated. The Kremlin has denied the allegations.

He is not eligible for release until at least 2016, but can apply for parole. Two separate appeals have already been rejected, however.

“Perjury is a grave sin," he said, responding to users’ questions on the website of the liberal radio station Ekho Moskvy. “By saving oneself this way, you drown others.”

“I will not buy freedom at the cost of perjury.”

He also hit out at life in present-day Russia, saying under Prime Minister Vladimir Putin things depended entirely on the “mindset, opinions and ambitions of one man."

Khodorkovsky, once Russia’s richest man, was seen as a potential challenger to Putin.

He said “attempts to save the empire” in Russia had brought it close to “national suicide.”

“As long as Russia retains its imperial syndrome, there will be no democracy.”