WASHINGTON, Aug. 20 (Xinhua) -- The U.S. Defense Department said on Wednesday that it had not found any clues showing close U.S. air support resulted in casualties among French troops ambushed in Afghanistan.

    "We have no reports of any casualties caused by close air support," said the Pentagon spokesman, Bryan Whitman.

    He made the remarks as a response to a report by the French newspaper Le Monde, saying that the injured French troops said NATO air strikes missed their targets and hit French troops.

    When asked whether French troops' casualties were resulted from the friendly fire, Whitman said that he had heard of "no report of that."

    The French forces were ambushed by about 100 insurgents on Monday when they were on a patrol in a U.S.-controlled sector east of Kabul, leaving 10 killed and 21 others injured, making it the deadliest attack on French troops since 1983.

    The Pentagon said on Tuesday that the U.S. air force in Afghanistan had provided air support to French forces during the fighting, which was "a complex attack involving multiple weapon systems, small arms, mortars, rockets" that lasted for several hours.

    It also said that the deadly attack underscore the need for the NATO-led International Security Assistance Force and the U.S. to continue the fight against the Taliban insurgents, among others, in Afghanistan.

    France has 3,000 troops deployed in Afghanistan currently, mostly in the Kabul area and Kapisa province.