NEW YORK, Mar. 5 (Xinhua) -- Crude prices retreated Thursday on weak U.S. economic readings.

    The Labor Department said new jobless claims and the total number of people receiving unemployment benefits both dropped unexpectedly last week. But the four-week average of new claims increased 2,000 to 641,750, the highest since October 1982.

    General Motors Corp., the largest U.S. car maker, said Thursday its auditors have raised "substantial doubt"' about the auto maker's ability to continue operations. GM said it may have to seek bankruptcy protection if it can't execute a huge restructuring plan.

    Light, sweet crude for April delivery fell 1.77 U.S. dollars to settle at 43.61 dollars a barrel on the New York Mercantile Exchange. In London, Brent prices tumbled 2.48 dollars to settle at 43.64 dollars on the ICE Futures exchange.