During the previous trading session both benchmarks rose to their highest levels since early June in choppy trading, having been pushed higher by data released on Wednesday showing U.S. crude and fuel inventories fell sharply last week.
Despite the drop, U.S. oil stocks, at roughly 490 million barrels, remain well above the five-year average, while U.S. production has increased almost 12 percent since mid-2016 to 9.4 million bpd.
Investors were also taking positions ahead of a meeting between OPEC and non-OPEC members in Russia on Monday at which they will discuss compliance with agreed production cuts and progress towards rebalancing an oversupplied market.
The market has been watching reports that the world's top crude producer,Saudi Arabia, is working with other countries to draw down stocks and reduce supply, particularly as other OPEC members, including Iraq and Libya, are planning increases in output.
OPEC members Iran and Kuwait are embroiled in a diplomatic spat that saw Kuwait ordering the expulsion of the Iranian ambassador and other diplomats for alleged links to a "spy and terror" cell.
The expulsions were an unusual move for Kuwait, which typically avoids conflict and has worked at keeping good relations with all countries in the region.
The tensions come just days ahead of the oil producers' meeting. OPEC, together with some non-members like Russia, has pledged to cut production by 1.8 million barrels per day (bpd) between January this year and March 2018.