Oil prices continued to fall in Asian trade on Thursday with investor sentiment under pressure from an unexpected jump in US crude stocks, analysts said.
New York's main futures contract, light sweet crude for October delivery, slipped 20 cents to 71.23 dollars a barrel.
Brent North Sea crude for delivery in October eased 39 cents to 71.26 dollars.
The two contracts had closed lower Wednesday after weekly data from the US Department of Energy (DoE) showing a rise in crude reserves.
"There hasn't been any drawback, inventories have increased... that's obviously surprised markets a little bit," said Ben Westmore, minerals and energy economist for the National Australia Bank in Melbourne.
"It doesn't look like the supply and demand balance in the US is improving... it doesn't really look like the massive supply overhang in the US will be resolved just yet," he said.
The DoE report released Wednesday showed US crude stockpiles rising by 200,000 barrels to 343.8 million in the week ending August 21, defying analysts' predictions of a 600,000-barrel drop.
A forecast by motorist group AAA that Americans would slash their early September Labor Day holiday travel plans as they tighten their belts was also weighing down crude prices, analysts said.
Some 39.1 million travellers were expected to take to the roads and air during the end-of-summer holiday, down a record 13.3 percent from a year ago, the AAA survey showed.