Oil prices dipped on because of unexpected rise in stocks of US motor fuel, but losses were limited by news that BP has further cut output at Prudhoe Bay, the US' biggest oil field.
At 1123 GMT, Brent North Sea crude for October delivery was down 3 cents at 71.99 dollars per barrel in electronic deals in London.
New York's main contract, light sweet crude for delivery in October, was meanwhile 7 cents lower at 71.79 usd per barrel in electronic deals before the official opening of the US market.
US gasoline (petrol) stocks showed a surprise gain of 400,000 barrels in the week to Aug 18, rising to 205.8 mln barrels, the Department of Energy said in its weekly report yesterday. Analysts had anticipated a decline of more than 2 mln barrels.
BP said that output at Prudhoe Bay, in Alaska, had fallen to about a quarter of normal output because of a new technical problem. A spokesman said that output had been cut by an extra 90,000 barrels per day at the field, bringing production down to about 110,000 bpd.