Russia is yet to decide on allowing private energy companies to explore offshore oil and gas fields, Kremlin spokesman Dmitry Peskov said on Thursday.

An existing law stipulates that only state energy majors Rosneft and Gazprom can explore offshore fields, but Lukoil, Russia's No.2 oil producer, has long called for allowing private firms as well.

Offshore drilling offers the prospect of future sources of production growth for Russia, which is now pumping more than 10 million barrels per day.

Yet western sanctions on Moscow for its role in the Ukrainian crisis ban foreign firms from in participating in the Arctic, deep water or in shale oil exploration.

Peskov said there had been no decision yet on allowing private companies to drill offshore. "Discussion is ongoing," he said, declining further comment.

Lukoil already operates on the Baltic Sea in Kaliningrad and on the Caspian Sea near the town of Astrakhan, rights the company obtained before the current law came into force in 2008.

The company has said it doubts Russia will be able to keep up current oil production levels, hurt by sanctions and the recent fall in oil prices.

Leonid Fedun, a co-owner of Lukoil, said earlier this month the drop in oil output could amount to as much as 800,000 barrels per day by the end of 2016, a prediction dismissed by Energy Minister Alexander Novak.