Russia's embattled oil giant Yukos says a Moscow court has frozen the company's stake in the Sibneft oil firm.

The business daily Vedomosti says the action could pave the way for the 34.5 percent stake to be seized if authorities prove it was acquired with illegal funds.

Yukos was to merge with Sibneft, but that deal was called off following the arrest last year of then-Yukos chief Mikhail Khodorkovsky. Mr. Khodorkovsky has remained in prison and is currently on trial for tax evasion and fraud.

Meanwhile, Yukos is struggling to pay billions of dollars in back taxes. Critics say the extensive probe is politically motivated because Mr. Khodorkovsky was a supporter of the political opposition. The Kremlin insists the actions are part of a crackdown on corruption.