Houston: The American Petroleum Institute (API) has reported an increase of 3.594 million barrels of crude oil in US inventories for the week ending October 29.
Analysts on Tuesday had expected an increase of about 1.567 million barrels for the week.
The API reported a surge of 2.318 million barrels in the previous week, Xinhua news agency reported.
Oil prices ended mixed on Tuesday as traders are awaiting US fuel stocks data and a key meeting of the Organization of the Petroleum Exporting Countries and its allies, collectively known as OPEC+.
The West Texas Intermediate for December delivery lost 14 cents to settle at 83.91$US a barrel on the New York Mercantile Exchange. Brent crude for January delivery increased 1 cent to close at 84.72 $ a barrel on the London ICE Futures Exchange.
The US Energy Information Administration is set to release its weekly petroleum status report on Wednesday, while OPEC+ is expected to meet on Thursday, discussing its plan on crude production.
Despite growing pressure from the major oil consuming countries, the alliance is expected to stick to its plan for gradual, monthly production increase of 4,00,000 barrels per day, according to analysts.