Moscow - Mikhail Khodorkovski, former head of the disbanded Yukos oil company and once reputedly the richest man in Russia, was in court Tuesday to face fresh charges of mishandling company funds.

Elaborate security was in place at the Moscow court for the appearance of the 46-year-old, an outspoken critic and political opponent of Prime Minister Vladimir Putin.

Khodorkovski, who has been imprisoned for more than five years, and his former business partner Platon Lebedev face charges of embezzling some 25 billion dollars.

The two were already sentenced to eight years' imprisonment in 2005 after being found guilty of fraud and tax evasion, and face a further 15 years if found guilty of the new charges.

Khodorkovski's defence team, family and associates have dismissed the new charges as politically motivated and absurd, brought in order to keep him behind bars.

The family have accused the Russian political establishment of wanting to silence Khodorkovski, scared that he is capable of exposing their own corruption in the face of criticism from a man who many see as a viable leadership alternative to Putin.

Before his arrest and imprisonment, Khodorkovski had been a co- financer of the Union of Just Forces (SPS), which late last year fused with two other parties - the Democratic party and the Citizens' Force - under the new party name "Just Cause". (dpa)