Russian President Vladimir Putin defended the takeover of the main oil pumping asset of Yukos, the country's largest oil company, saying the state was just "ensuring its interests."

Putin's comments to reporters came after state-owned Rosneft took control of a company that last weekend bought the rich oil pumping subsidiary of Yukos for $9.3 billion US.

Russian President Vladimir Putin
Russian President Vladimir Putin

It was the first major company the Russian government has nationalized since the fall of the Soviet Union in 1991.

"Today, the state, using absolutely legal, market mechanisms, is ensuring its interests," Putin said at his annual news conference. "I consider this perfectly normal."

The Kremlin has been targeting Yukos and its top management for more than a year. Putin and close officials have accused the company of illegally scooping up Russia's oil properties for a fraction of their true value after the Soviet Union collapsed – a charge the Russian president repeated Thursday.

"Some market participants got multi-billion state assets using different tricks, including some violations of then-existing legislation," Putin said.

Yukos founder Mikhail Khodorkovsky has been in a Russian prison since October 2003, charged with fraud and tax evasion over his running of the company.

But Khodorkovsky was known to have strong political ambitions and critics say the roots of Putin's attacks on Yukos and Khodorkovsky have always been more political than economic.

Rosneft is in the process of merging with Gazprom, the state-owned oil and gas monopoly. Gazprom had been expected to bid for the oil pumping arm of Yukos at an auction last Sunday. But the company did not follow through on a bid after a U.S. court granted a Yukos request for an injunction.

Yukos, which has filed for Chapter 11 bankruptcy protection in the United States, faces a Kremlin demand for $28 billion US in back taxes and penalties.

In Washington, U.S. officials denounced the takeover, saying it lacked transparency and undermines Russia's standing in the world economy.