Both contracts fell more than 4% on Monday, the most in two weeks.
Oil prices fell on Wednesday after an industry group reported a rise in U.S. crude inventories against expectations for a decline, adding to worries about demand that led to a steep selloff earlier in the week.
Brent crude was trading down 21 cents, or 0.5%, at $41.51 a barrel by 0055 GMT, after gaining 28 cents on Tuesday, while U.S. crude slipped 23 cents, or 0.6, to $39.57, as reported by Reuters.
Both contracts fell more than 4% on Monday, the most in two weeks.
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In the United States, where the death toll from COVID-19 has passed 200,000, the world's highest, crude oil inventories rose by 691,000 barrels in the week to Sept. 18, according to industry data, compared with analysts' forecasts for a drop of 2.3 million barrels.
Gasoline stocks fell by nearly 7.7 million barrels, nearly 8 times expectations suggesting some demand for fuel in the world's biggest oil consuming nation.