Washington, Sep 28 : A football player was killed and three others were injured after gunmen ambushed them outside a high school in Philadelphia, the US state of Pennsylvania, police said. The shooting happened on Tuesday at 4:30 p.m. local time outside Roxborough High School, reportedly after a football scrimmage ended. Police added that the players were walking off the field when occupants of a vehicle ambushed them, Xinhua news agency reported. Officers found two 14-year-olds, a 17-year-old, and another victim suffering from gunshot wounds, according to preliminary information from authorities. The victims were taken to the hospital. One of the 14-year-olds, a male, was pronounced dead later. No arrests have been made. Nearly 33,000 people, including more than 1,200 children and teenagers, have died across the US due to gun violence so far this year, according to Gun Violence Archive. /IANS