It said daily natural gas output at the field now stood at around 1.8 million cubic metres per day. It has not provided comparison with previous levels.

Rosneft is leading the Vostok Oil project that is comparable in size to the exploration of West Siberia in the 1970s or the U.S. Bakken oil region over the past decade.

The company, headed by Igor Sechin, a long-standing ally of President Vladimir Putin, plans to tranship annually some 30 million tonnes (600,000 barrels per day) of oil via the yet-to-be-built Bukhta Sever port initially with a gradual increase to 100 million tonnes by 2030 as part of the Vostok Oil project.

(Reporting by Vladimir Soldatkin; editing by David Evans)