MEXICO CITY (Reuters) - A Mexican military helicopter crashed on Friday in the northern state of Durango, seriously injuring one military member aboard and likely killing seven others, the defense ministry said in a statement. The helicopter, a Bell 412 model, crashed 4 kilometers (2.5 miles) northeast of the town of El Salto in the mountainous state of Durango during a training flight. The one survivor was in grave condition in hospital, while authorities are searching for the bodies of seven other military members which were presumed to be among the remains of the aircraft. The northern state of Durango borders Sinaloa state, home of the Sinaloa drug cartel. Military authorities are investigating what happened to the helicopter, the ministry said. 