ST.PETERSBURG, Russia (AP) — The head of Russia's state-controlled Rosneft oil giant says that that a rise in shale oil output in the U.S. would likely offset the effect from OPEC production cuts.

Speaking Friday at an economic forum in St.Petersburg, Rosneft CEO Igor Sechin said thanks to increasing efficiency U.S. shale oil producers would likely deliver an additional 1.5 million barrels of crude a day to the market in 2018.

OPEC and 10 other countries led by Russia agreed last week to extend for nine months, to March, a production cut of 1.8 million barrels a day initially agreed on in November. The move is a bid to shore up oil prices.

Sechin said the cuts fall short of "systemic measures that would lead to long term stabilization."