Russian state-controlled oil firm Rosneft has won the latest auction for assets from bankrupt oil firm Yukos.
The auction took place at Yukos' headquarters in Moscow
Rosneft subsidiary Neft Activ outbid little-known company Unitex for East Siberian oil and gas firm Tomskneft and other production and refining units.
Rosneft tabled a winning bid of 175.7bn roubles ($6.8bn; £3.4bn).
The Russian state has been selling off Yukos assets in order to pay off a huge $26bn back tax bill, which led to the firm being liquidated last year.
Yukos was declared bankrupt following a series of fraud inquiries, which also led to its founder and former chief Mikhail Khodorkovsky being jailed.
Yukos says the tax demands were linked to a political campaign against Mr Khodorkovsky, who is currently serving a long prison sentence in Siberia.
Analysts say that with the latest sell-off Rosneft has tightened its control over Russia's energy assets.
As well as Tomskneft - which produces about 233,000 barrels of oil a day - the group also picked up two refineries and other smaller assets in eastern Siberia.