A U.S. helicopter crashed in this northern Iraqi city Saturday, the military said. There was no word on the cause of the crash or possible casualties. “A quick reaction force is securing the area,” said a military spokesman who spoke on condition of anonymity. Witnesses said the helicopter came down in Borsa, a residential neighborhood in Mosul, Iraq’s third-largest city. “I was leaving the mosque and I heard a boom,” said Hani, a witness who only gave his first name. He said that two helicopters collided in mid-air before one crashed onto the roof of a house, adding that he did not know what happened to the other aircraft. Full Story