British energy group BP said on Monday it remained committed to its investment in Rosneft, despite new sanctions imposed by the United States against the Russian oil giant's chief executive Igor Sechin.

The powerful head of Russia's largest oil company was one of seven senior officials named on a new list of US punitive measures aimed at punishing President Vladimir Putin's stance on Ukraine.

Rosneft itself did not face any new restrictions. Washington's measure freezes any holdings Sechin might have in the United States and bars him from entering the country.

BP said that it was studying what impact the US announcement might have on its 19.75-percent holding in the state-held company.

"We remain committed to our investment in Rosneft and intend to remain a successful long-term investor in Russia," the British firm said in a statement quoted by Russian news agencies.

"We are studying today's announcement in order to understand what exactly it might mean for BP."

The British group boosted its holding in Rosneft after selling its half in the TNK-BP joint venture to the Russian firm last year.

The deal left BP head Robert Dudley holding a non-executive seat on the Rosneft board.

Sechin himself suggested with a hint of sarcasm that the sanctions reflected fears in the White House of the Russian firm preparing to conquer US production and domestic sales markets.

"We understand that the US administration has noticed our company's active efforts to reduce risks" by expanding activities beyond Rosneft's traditional European and Asian markets, Russian news agencies quoted Sechin as telling reporters.

"We view Washington's steps as a positive assessment of the high efficiency of our work," Sechin added.

Rosneft has signed a strategic cooperation agreement with the US super-major ExxonMobil and is planning to launch joint production projects in North America.

The Russian company's shares lost about one percent of their value on the Moscow Exchange after Washington unveiled its sanctions list.