At least six people were killed and three critically injured when two medical helicopters were involved in a mid-air collision in Flagstaff, Arizona, the Federal Aviation Administration said on Monday.
Map locates Flagstaff, Ariz., where two helicopters collided killing at least seven people.
The exact number of fatalities is still unclear with some local radio stations putting the death toll at seven. It is believed a patient, helicopter pilot and medic are among the dead.
The two choppers fell in woodland near a local hospital and exploded, injuring two rescuers. The blast caused a wildfire which is currently being tackled by firefighters.
The Flagstaff Medical Center does not have any air traffic controllers.