Energy Information Administration data showed US commercial oil inventories (excluding the strategic reserve) fell by 3.3 million barrels, or 0.8%, to 421.7 million barrels by the end of last week.
Analysts polled by the DailyFX portal had expected a reduction in inventories of just 930,000 barrels.
The US Strategic Petroleum Reserve also fell by 8.1 million barrels, or 1.8%, to 453.1 million barrels, according to the US Department of Energy.
The ministry said U.S. oil production fell by 100,000 bpd to 12 million bpd in the week ending August 19.
US oil production over the past four weeks averaged 12.1 million barrels per day.
Source: Prime