At least one U.S. marine was killed and 14 others injured when a UH-60 Black Hawk helicopter crashed on Friday in the south-eastern Afghan province of Khost, U.S. military officials said. In a statement issued in Kabul, the U.S.-led coalition forces said that the injured service members were transported to Forward Operating Base Salerno, a coalition base in Khost. Four soldiers had injuries serious enough to require further evacuation to the hospital at Bagram Air Field, 50 kilometres north of Kabul, the statement said, adding that the extent of their injuries was unknown. The helicopter was destroyed in the crash, but did not burn. Hostile fire was not involved, the statement said, adding that the cause of the crash is under investigation. Attack helicopters and Marines on the ground secured the crash site.