Video Related To: Two more Americans killed by insider 'green-on-blue' attack in Afghanistan

A US military helicopter crashed during a firefight with insurgents in a remote area of southern Afghanistan on Thursday, killing seven Americans and four Afghans in one of the deadliest air disasters of a war now into its second decade. The Taliban claimed they gunned down the Black Hawk. American service personnel in Afghanistan are dying at a rate of about one per day so far this year despite a drawdown of troops. That death rate has risen recently with the summer fighting season in full gear and a rash of attacks by Afghan security forces on their foreign trainers and partners. NATO forces said they could not confirm what caused Thursday's crash and stressed that it was still being investigated. The Black Hawk was operating in support of an ongoing assault on the ground but initial indications were that it was not shot down, according to US officials who spoke anonymously because the investigation was continuing. Taliban spokesman Qari Yousef Ahmadi said insurgent fighters struck the helicopter in Kandahar province on Thursday morning. He declined to give further details in a phone call with The Associated Press. The Kandahar provincial government backed the Taliban claim. It said the helicopter was shot down in Shah Wali Kot district, a rural area north of Kandahar city where insurgents move freely and regularly launch attacks. Provincial spokesman Ahmad Jawed Faisal did not provide details or say how the province had confirmed the information. Kandahar is a <b>...</b>