The owners of Russia's embattled oil company Yukos say they have filed a claim of $28 billion against the Russian government. A top official with the Yukos holding company, Group Menatep says the action was filed under the Energy Charter Treaty, an international agreement aimed at protecting investors' rights. Russia has not ratified the pact.

Menatep charges that Yukos was worth $17 billion in October 2003, at the time of the arrest of the company's then-chief, and is nearly worthless now. Former Yukos head Mikhail Khodorkovsky, who supported the political opposition, remains jailed on charges of tax evasion and fraud.

The Russian government has sought more than $27 billion in back taxes from Yukos, and sold its key production unit at a court-ordered auction in December. Critics call the government actions against Yukos politically motivated. The Kremlin says it is part of a battle against corporate corruption.

Some information for this report provided by AFP and AP.