NEW YORK, Aug. 17 (Xinhua) -- Oil prices expended its losses on Monday as global equities fell and the dollar strengthened against a basket of major currencies.

    Light, sweet crude for September delivery tumbled more than 3 percent during the session before rebounding to settle at 66.75 dollars a barrel on the New York Mercantile Exchange.

    Oil prices slid to an intra-day low of 65.23 dollars a barrel as the Standard & Poor's 500 Index fell 2.3 percent after China's Shanghai Composite Index slumped 5.8 percent, the most since November, spurring more concerns about the world economy.

    Meanwhile, the dollar continued its rally for a second session, reducing the appeal of crude as an alternative investment to hedge against inflation and encouraging selling off in the commodities markets.

    In London, Brent Crude for September delivery dropped 1.94 dollars to 70.47 dollars a barrel on the ICE Futures exchange.