Oil prices slipped for a third day on Wednesday as a surge in U.S. stockpiles reinforced concerns about lackluster global economic growth, while hopes ebbed for any movement on the U.S.-China trade war.

West Texas Intermediate (WTI) crude futures CLc1 erased early gains to be down 6 cents, or 0.1%, at $55.15 a barrel by 0631 GMT, after falling more than 4% over the previous two sessions, Reuters said.

Brent crude futures LCOc1 were at $60.71 a barrel, down 20 cents, or 0.3%. Brent dropped 3.8% during the prior two sessions.

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Crude inventories in the United States, the world's biggest oil user, rose 6 million barrels in the week to November 15 to 445.9 million, data from industry group the American Petroleum Institute showed late on Tuesday.

The increase added to concerns about crude oversupply after Reuters reported that Russia, the world's second-biggest producer, was unlikely to back deepening output cuts when the Organization of the Petroleum Exporting Countries (OPEC) meets in Vienna on December 5-6.

Russia and other oil producers have agreed with OPEC to cut 1.2 million barrels per day of output through March to bolster prices, a producer group known as OPEC+.

Official U.S. government inventory data from the Energy Information Administration is due at 10:30 a.m. EST on Wednesday.

U.S. crude demand has slowed during a protracted trade war with China. Hopes for an end to the dispute in the signing of a so-called Phase 1 agreement between the sides has dimmed amid disagreements over the removal of tariffs.