A Moscow court has extended the house arrest of Russian billionaire Vladimir Yevtushenkov for another four months.

The court said he is a flight risk or might try to influence witnesses.

Yevtushenkov is accused of money laundering over the 2009 purchase by his Sistema conglomerate of former state oil producer Bashneft.

Prosecutors say that sale was illegal and have seized Yevtushenkov’s shares in the oil company.

Kremlin critics believe he has been caught in the middle of moves by the government to regain control of oil and gas assets sold off in the rapid and chaotic privatisations of the 1990s.