Oil resumed its slide on Monday as investors remained uncertain whether producing nations will extend an OPEC-led output cut beyond the end of June in an effort to reduce a global glut of crude.
On Sunday, a committee of ministers from OPEC and outside producers agreed to look at prolonging the deal, stopping short of an earlier draft statement that recommended keeping the measure in place.
Oil prices have been falling since the middle of the month, as a spate of reports showing stronger-than-expected growth in U.S. inventories sparked selling from speculators that had build record long positions in crude futures.
Last week's futures data showed speculators were still unwinding long positions, or bets that prices will rise, as high U.S. inventories offset cuts from other oil producers. Long positions as of last Tuesday were at their lowest since December.