Investing.com - Oil was lower Monday as OPEC's monthly report indicated a high compliance level with the cartel's agreed output cuts in January.
Brent crude was off 47 cents, or 0.83%, at $56.23 at 08:30 ET. U.S. crude shed 38 cents, or 0.71%, to $53.48.
OPEC cited secondary sources as estimating a cut of 890,000 barrels in January to 32.14 million barrels a day.
OPEC began implementing cuts of 1.16 million barrels per day at the start of this year for a period of six months.
The International Energy Agency last week estimated a record compliance level with the cuts in January by OPEC.
Non-OPEC members led by Russia have also agreed to reduce production by 558,000 barrels a day.
Baker Hughes U.S. rig count figures Friday showed an increase of 8 to 591.
That was the highest level since November 2015. OPEC estimated higher non-OPEC output this year on increased U.S. drilling activity.