Crude oil fell on Thursday, pressured by ample supply, concerns about demand growth and a stronger U.S. dollar.
Brent prices slid sharply early in the day, dropping 60 cents a barrel within 13 minutes, while West Texas Intermediate (WTI) tumbled 90 cents over the same period.
Reasons for the sudden dive were not immediately clear. Traders pinned at least part of it on the U.S. dollar's rally to its highest in more than four years against a basket of currencies. The dollar drew support from a fall in U.S. jobless claims and Federal Reserve interest rate forecasts that were higher than those predicted in June.
The decline in the global benchmark Brent price was limited by a drop in Libya's output and talk of OPEC production cuts. Brent hit a 26-month low on Monday after data showing a slowdown in China's factory output raised demand concerns.
A stronger dollar makes dollar-priced commodities such as oil more expensive for buyers using other currencies.
"I think currencies are the focus," said Richard Ilczyszyn, chief market strategist and founder of iitrader.com LLC in Chicago. "The bottom line is that with the stronger dollar and dollar index basket rally... you can just take 10 percent off the top of commodity prices across the board. With all the geopolitical risk escalating overseas, oil should be popping. But (the falls are) all currency as far as I'm concerned."