Exxon Mobil can operate freely with Russian energy company Rosneft at a Far East energy project without fear from sanctions, a spokesman said.

The Sakhalin-1 project envisions the development of three oil and natural gas fields located in extreme sub-Arctic conditions off the coast of Sakhalin in Russia's Far East. Alan Jeffers, a spokesman for project partner Exxon Mobil, said Monday the company was isolated from the economic impact of Western pressure.

"The Sakhalin-1 project is not impacted by U.S. sanctions," he told state news agency RIA Novosti.

Western governments blacklisted Rosneft and other Russian energy companies in response to the Kremlin's stance on the separatist campaign in eastern Ukraine. In mid-September, the European Union took additional steps by barring Russian oil company Rosneft and its counterparts Transneft and Gazprom Neft from working in European capital markets.

Rosneft is working alongside Rosneft on nearly a dozen projects in Russia. In the arctic reaches of the Kara Sea, Russian Deputy Energy Minister Kirill Molodtsov said there are enough Russian rigs in the area to continue should Exxon drop out under sanctions pressure.