Oil prices decreased on Wednesday over a build in US crude inventories and doubts over whether the release from emergency reserves can curb rising gasoline prices in the US.

International benchmark Brent crude was trading at $81.98 per barrel at 0645 GMT for a 0.54% fall after closing the previous session at $82.43 a barrel.

American benchmark West Texas Intermediate (WTI) was at $79.28 per barrel at the same time for a 0.6% drop after trade ended at $79.74 a barrel in the previous session.

Prices started the week on a negative note and crude then came under pressure as the American Petroleum Institute (API) announced late Tuesday its estimate of a build of 655,000 barrels in US gasoline inventories for the week ended Nov. 9.

This amount is less than the forecast 1.55 million-barrel build and the 2.48 million-barrel draw reported the previous week.

The forecast of an inventory build signals sluggish crude demand in the US, which, in turn, is putting downward pressure on prices.

The US Energy Information Administration (EIA) will release official oil stock data later on Wednesday. Oil prices are expected to continue falling if the EIA signals a build in stocks.

Doubts over whether the US will release oil from its Strategic Petroleum Reserve (SPR) also support the downward trend in prices.

As opinions continue to be divided over the move, experts argue that the SPR is for emergency use only and this action to balance the supply/demand gap would only be short-lived.

The US has the world's largest SPR of more than 600 million barrels stored in huge underground salt caverns at four sites located on the Gulf of Mexico coast./aa