Oil dropped in price by more than 3% to under $US61 per barrel on Wednesday.
US crude settled $US2.79 lower at $US60.14 per barrel for its sixth consecutive daily fall. The close was the lowest since $US59.65 per barrel on 19 May.
London Brent crude settled at $US60.43 per barrel, down $US2.80.
Distillate stocks in the United States, including diesel, rose by 3.7 million barrels last week - the highest in almost 25 years.
A weekly report issued by the Energy Information Administration also showed gasoline stocks rose by 1.9 million barrels despite the 4 July holiday weekend.
Meanwhile, OPEC expects consumption of crude oil will not return to average 2008 levels (31 million barrels per day) until 2013.
