Oil prices dived Wednesday as a government report showed that U.S. crude stockpiles of last week increased unexpectedly.

U.S. crude supplies of last week gained 2.6 million barrels to 456.2 million, 93.7 million barrels more than one year ago, according to the Energy Information Administration (EIA)'s Wednesday weekly report.

Inventories at Cushing, Oklahoma, the delivery point for the U.S. contract added 0.32 million barrels to 57.1 million barrels.

U.S. crude production fell 47,000 barrels to 9.348 million barrels a day that week.

U.S. oil companies added more oil rigs last week despite the plummet in crude prices. Data showed last week a rise of 2 in the number of active U.S. oil drilling rigs to 672, according to a report from oil services company Baker Hughes.

The West Texas Intermediate for September delivery moved down 1.82 U.S. dollars to settle at 40.8 dollars a barrel on the New York Mercantile Exchange, while Brent crude for September delivery decreased 1.65 dollars to close at 47.16 dollars a barrel on the London ICE Future Exchange.