An IDF soldier was seriously wounded, another moderately wounded and three lightly wounded in the Gaza Strip Saturday afternoon, by anti-tank missiles fired by Hamas combatants. The soldiers, all from the Givati Brigade, were evacuated for medical treatment in Israeli hospitals. Earlier Saturday, four troops from the IDF's Paratroopers Division were seriously wounded during clashes with Hamas gunmen close to Gaza City. The four - two officers and two soldiers - were hurt from mortar shell fire. The IDF is investigating the incident and has not ruled out friendly fire. Overnight Friday, an IDF soldier was evacuated to an Israeli hospital in moderate condition after being wounded during Gaza fighting. Earlier, Palestinian sources claimed that two people were killed and 14 wounded by Israeli forces. The reports came following an alleged artillery strike near a UN school for boys which the army had yet to comment on. UN spokesman Chris Gunness, said the school was crowded with 1,600 people. He said the compound took several direct hits, and two people died. Gunness says Israel had the coordinates of the school and knew it was being used as a shelter. He said there should be an investigation into possible war crimes, and that anyone who is guilty should be brought to justice. Meanwhile, the air force attacked 50 Hamas targets throughout the Strip, sources said Saturday morning. Among the targets, mostly in northern Gaza, IAF planes bombed rocket launching pads, weapons smuggling tunnels and weapons caches.