Russian oil company Rosneft said it may have to postpone some projects because of "volatility" associated with economic sanctions.

Washington announced another set of tough new sanctions on Russia in coordination with its allies in the European Union.

U.S. President Barack Obama said the sanctions would target Russian banks and exports of goods and technology for the Russian energy sector in response to Moscow's position on crises in Ukraine.

"If Russia continues on its current path, the cost on Russia will continue to grow," he said.

The pressure comes more than a week after Washington issued sanctions against the financial arm of Russian gas company Gazprom, gas producer Novatek and oil company Rosneft.

Rosneft Chief Executive Officer Igor Sechin, himself the target of U.S. sanctions, said the company's strategy was impeded by sanctions.

"We work under different conditions and are ready for volatility linked to the sanctions," he said Tuesday. "We'll work for better efficiency, postpone some projects, but effective work will be our priority."

The Russian Central Bank said it was prepared to prop up financial institutions burdened by economic pressure from Washington.

"Adequate measures will be taken, if necessary, to support these organizations to protect the interests of their clients, depositors and creditors," the bank said.