Raids on the offices of British oil giant BP in Moscow on March 21 were conducted by secret service agents and may be part of a looming "redistribution" of oil assets in Russia, newspapers said.
"Market sources do not exclude that the measures could be a new serious step in the redistribution of assets in large companies" as President Vladimir Putin prepares to leave power in May, the Vremya Novostei daily said.
An interior ministry spokeswoman told AFP that the raids on BP and its joint venture TNK-BP were part of a long-running criminal inquiry into Sidanko, a company that was merged to form TNK-BP in 2003.
But Russian newspapers did not find that argument convincing and quoted officials within the company as well as security officers saying that the Sidanko inquiry has long been wrapped up.
TNK-BP, which is jointly owned by BP and a group of Russian billionaires, has faced growing pressure in Russia, where the oil and gas business is coming increasingly under state control.
TNK-BP is Russia's third largest oil company after Rosneft and Lukoil.
Kommersant cited sources at TNK-BP saying that the raids could be aimed at reducing the share price so that part of the company could be sold off more cheaply to state-run gas monopoly Gazprom. Shares in TNK-BP fell nearly 10 percent on the Russian stock exchange after news of the raids. The raids come amid widespread speculation on the future of TNK-BP amid a transition of political power in Russia.
Kommersant's sources also said the raids could be an attempt by TNK-BP's Russian owners to "frighten the English," adding that investigators were interested mainly in foreigners' access to information on energy deposits.
TNK-BP has already been the subject of inquiries by the FSB secret service for alleged breaches of Russian laws on state secrets, which forbid foreigners from accessing information about Russia's energy reserves.
"The investigations in both companies are agreed at the highest level and are part of an attempt to push BP out of the Russian oil market," RBK Daily quoted a source close to TNK-BP shareholders as saying.