Crude prices came under renewed selling pressure Monday after OPEC said it would not cut oil output despite fears of a glut, and a UAE official opposed holding an emergency meeting of the producer group to fix prices.
U.S. crude settled down $1.90 at $55.91 per barrel, the lowest settlement since May 2009. The contract slide further in after-hours trading.
Benchmark Brent oil was down 65 cents at $61.20. It had risen as much as $1.40 earlier to $63.25 after a session low at $60.28, a bottom since July 2009.
"You have all these OPEC officials reiterating they are not going to cut production, so you are seeing selling into the rallies," said Phil Flynn, analyst at Price Futures Group in Chicago.
Abdullah al-Badri, secretary-general of the Organization of the Petroleum Exporting Countries, said the group could ride out an oil price slump since June of nearly 50 percent without amending production. Influenced by top exporter Saudi Arabia, OPEC decided last month that cutting output meant losing its market share.
Suhail Bin Mohammed al-Mazroui, oil minister of the United Arab Emirates, later said there was no need for an emergency OPEC meeting to help support prices.