Oil prices extended losses on Thursday to hit two-week lows as investors fretted about global growth prospects and industry data showed crude inventories rose more than expected in the week to Oct. 5.
Crude oil futures for November delivery fell 1.68 percent to $71.94 a barrel, adding to a 2.4 percent slide overnight as escalating tensions between the U.S. and China raised concerns that global oil demand will decline in the near term.
Brent crude was down 1.75 percent at $81.66 a barrel after closing 2.2 percent lower on Wednesday amid easing supply worries as Hurricane Michael likely spared oil assets from significant damage.
U.S. crude inventories climbed by 9.7 million barrels to 410.7 million last week, the American Petroleum Institute said on Wednesday. That compared with analyst expectations for an increase of 2.6 million barrels.
The U.S. Energy Information Administration (EIA) is due to release official government inventory data later today.