New York's main contract, light sweet crude for delivery in September, dipped 79 cents to $82.10 per barrel.
Brent North Sea crude for September delivery fell $1.10 to $105.58.
"The current decline is some pull back after we saw the Dow Jones (Industrial Average) drop by four percent yesterday," said Ker Chung Yang, commodity analyst for Phillip Futures in Singapore.
"I think markets are being weighed down by global equities markets... market sentiment is still uncertain as to what's going to happen in Europe and the US," he told AFP.
US stocks plummeted over four percent Wednesday, more than wiping out a rebound as European debt troubles and worries of a new US recession kept investors nervous.
The Dow Jones Industrial Average closed down 519.83 points (4.62 percent) to 10,719.94, reversing its 430-point gain on Tuesday, and the broader S&P 500 fell 51.77 points (4.42 percent) to 1,120.76.
The tech-heavy Nasdaq lost 4.09 percent, or 101.47 points, to 2,381.05.
Asian equities markets were also hammered, with South Korean, Chinese, Hong Kong, Japanese and Australian bourses down by one to four percent in early trade Thursday.
In Europe, worries over debt contagion surfaced yet again after cracks appeared in Greece's latest bailout package and rumours abounded in France that Paris, and possibly its banks, would also be downgraded as the United States was on Friday.
Copyright AFP (Agence France-Presse), 2011