The West Texas Intermediate (WTI) for July delivery increased 71 cents to settle at 40.46 U.S. dollars a barrel on the New York Mercantile Exchange. The July contract for the U.S. benchmark expired at the end of the session.
The new front-month August WTI contract settled 90 cents higher at 40.73 dollars a barrel.
Meanwhile, Brent crude for August delivery rose 89 cents to close at 43.08 dollars a barrel on the London ICE Futures Exchange.
In the week ending Friday, the WTI advanced 9.6 percent and Brent gained 8.9 percent.
"Good production discipline on the part of OPEC+ coupled with a massive involuntary reduction in production in the U.S. on the one hand, plus the rapid recovery of demand on the other, have caused supply surpluses to be eroded significantly more quickly than anticipated," Eugen Weinberg, an energy analyst at Commerzbank Research, said in a note Monday.
Earlier this month, the Organization of the Petroleum Exporting Countries and its allies led by Russia, known as OPEC+, agreed to extend the historic 9.7 million barrels per day production cut till the end of July.
Oilfield services company Baker Hughes said Friday that the number of active U.S. rigs drilling for oil declined by 10 to 189 in the latest week. The total active U.S. rig count fell by 13 to 266.