US crude fell by 16¢ to stand at $88.77 while Brent crude dropped 6¢ to $114.13 a barrel as investors await US employment data.

Weak data may prompt the Federal Reserve to start a fresh round of policy easing at its next meeting on 20 September 2011, reports Reuters.

Investors are also keeping an eye on the potential supply disruption in the Gulf of Mexico after Hurricane Irene shut nearly 6% of output in the key producing region.