In tonnes, oil output reached 45.975 million versus 47.783 million in March, which is a day longer.

Russia has pledged to reduce its oil output by 228,000 bpd to around 11.18 million bpd from some 11.41 million bpd it pumped in October 2018, the baseline for the current agreement.

The Organization of the Petroleum Exporting Countries (OPEC) and other large oil producers led by Russia agreed to reduce their combined oil output by 1.2 million bpd starting from Jan. 1 for the next six months to evenly balance the market.

Several Russian officials including Kirill Dmitriev, head of Russian sovereign wealth fund RDIF, have signalled that Russia wants to raise its output due to improving market conditions.

Dmitriev and energy minister Alexander Novak have come under increased pressure over the past year from firms such as Rosneft , whose boss Igor Sechin, a close ally of President Vladimir Putin, has said Russia should abandon output cuts.

Gazprom Neft, Russia's fastest growing oil producer in terms of output, also added to the pressure, saying it assumed the cuts deal is effective only until the middle of this year.

The next full-scale meeting of OPEC and non-OPEC nations is due to take place in Vienna in the end of June.

OPEC oil supply hit a four-year low in April, a Reuters survey found, due to further involuntary declines in sanctions-hit Iran and Venezuela and output restraint by top exporter Saudi Arabia.

Natural gas production in Russia was at 64.3 billion cubic metres (bcm) last month,or 2.14 bcm a day, versus 65.68 bcm in March.