Officials from the United Nations and the Palestinian government said 16 people were killed and hundreds wounded on Thursday when the school in northern Gaza was struck. The Israeli military denied that it was responsible for anyone killed last week when a mortar hit the courtyard of a U.N. school that was shelter to many Gaza residents. "A single errant Israeli mortar landed in the courtyard in the school," Israel Defense Forces spokesman Lt. Col. Peter Lerner said. "The footage we have shows the courtyard was empty." Lerner said there was fierce fighting between the IDF and Hamas on Thursday. The militants fired anti-tank missiles from the immediate vicinity of the school and the IDF fired several mortars in that direction.