A Russian judge has pronounced Mikhail Khodorkovsky and his business partner Platon Lebedev guilty of embezzlement at the end of the jailed former oil tycoon's politically charged second trial.

The judge said the two men were also guilty of laundering stolen oil funds.

The accusation of stealing oil from his now-defunct company Yukos was the main charge against Khodorkovsky in a trial seen as a test of the Kremlin's will to impose the rule of law.

Prosecutors have asked the judge to sentence Khodorkovsky to six more years in prison on top of the eight years he is serving now.

Reading the verdict judge Viktor Danilkin said the court had established that Khodorkovsky and Lebedev "carried out the embezzlement of property entrusted to the defendants."

Enclosed in a glass-and-steel courtroom cage, Khodorkovsky and Lebedev pointedly ignored the judge as he read out the widely expected guilty verdict, whispering to one another and reading books and documents.

A crowd of a few hundred supporters outside the courthouse chanted "Freedom!".

Khodorkovsky, once Russia's richest man and head of its biggest oil producer, is nearing the end of an eight-year sentence imposed in a fraud and tax-evasion trial that shaped Vladimir Putin's 2000-2008 presidency.

In his new trial, prosecutors argued he stole $27 billion in oil from Yukos subsidiaries through pricing schemes. His lawyers dismiss the charges as an absurd, politically motivated pretext to keep him behind bars.