Oil prices declined on a stronger U.S. dollar and on concerns over the global oil glut. The U.S. dollar rose against other currencies after the release of the U.S. retail sales. The U.S. retail sales climbed 0.6% in July, exceeding expectations for a 0.5% increase, after a flat reading in June. June's figure was revised up from a 0.3% drop.

The increase was partly driven by higher automobiles purchases. Automobiles sales rose 1.4% in July.

Retail sales excluding automobiles increased 0.4% in July, in line with forecasts, after a 0.4% gain in June. June's figure was revised up from a 0.1% decrease.

These figures could add to speculation on that the Fed starts raising its interest rate next month.

BP's refinery in Whiting, Indiana faced problems, which could lead to higher U.S. crude oil inventories. The capacity of the refinery is 165,000 barrels per day.

News that Iraq plans to export near-record oil volumes in September also weighed on oil prices.

WTI crude oil for September delivery fell to $42.37 a barrel on the New York Mercantile Exchange.

Brent crude oil for September decreased to $49.00 a barrel on ICE Futures Europe.