Oil prices declined on Friday after rising U.S. rig count triggered market concern over global oil glut.

U.S. rigs classified as drilling for oil this week are up 8 from last week to 617, its highest since September 2015, said the oilfield service company Baker Hughes on Friday.

For the week, the U.S. crude price dropped nearly nine percent. Analysts said the continuously falling price cast doubt on whether the Organization of the Petroleum Exporting Countries will extend their output cuts efforts to the second half of this year.

The West Texas Intermediate for April Delivery erased 0.79 U.S. dollars to settle at 48.49 dollars a barrel on the New York Mercantile Exchange, while Brent crude for May delivery decreased 0.82 dollars to close at 51.37 dollars a barrel on the London ICE Futures Exchange.