Four U.S. soldiers were wounded when a car bomb targeting their convoy exploded in this northern city Tuesday, the U.S. military said. U.S. troops opened fire after the explosion, killing three Iraqis in a passing vehicle and wounding a number of others in the city's Yarmuk neighborhood, said police 2nd Lt. Mohammed Ahmed. Mohamed Qadir Youssef, a worker at Yarmuk's Al-Gomhuria Hospital, said three persons were killed and three others wounded in the incident. Capt. Angela Bowman, a military spokeswoman, denied U.S. troops opened fire against civilians in the area. She said the four wounded soldiers, who were not identified, were evacuated to a military hospital in Mosul. The blast occurred at midday at a traffic circle in Yarmuk, she said.