Oil prices fell on Monday as spare oil storage capacity runs low and a potential agreement in nuclear talks with Tehran opened the prospect of more Iranian exports, should sanctions be eased.
U.S. crude fell to $43.57 in early trading, its lowest since March 2009, before rebounding to $44.19 by 0658 GMT, still down 65 cents. Brent was trading at $54.26 a barrel, down 41 cents.
Western powers are hoping for concessions from Tehran that could help clinch a political agreement in nuclear talks this week after the United States and European powers voiced a willingness to compromise on suspending U.N. sanctions, which also affect oil exports.
"The prospect of an increase in Iranian oil sales as part of a new agreement in the next couple of months will only exacerbate OPEC oversupply, supporting our bearish outlook," Barclays said.
The World Petroleum Council said that the low prices would lead to investment cuts.