The UN Secretary General Ban Ki Moon says he's appalled by an Israeli attack on a United Nations school in Gaza - in which 15 people were killed.
The dead included a baby and 3 teachers.
A UN official confirmed there were "multiple dead and injured" in the attack on a school in the city of Beit Hanun.
Another UN official said the agency had tried to urge people to leave the building earlier, fearing it may be "a potential target".
The facility was being used as a shelter by hundreds of Palestinians fleeing a major Israeli operation in the area.
At least 150 people were injured in the blast - the fourth time a UN facility has been hit during the start of the recent conflict.
Speaking earlier, UN Spokesperson Chris Gunness said any attacks on UN property should be fully investigated.
"There should be a full and proper and authoritative and independent investigation to discover exactly what went on" he said.
"And can I moreover say that the combatants to this conflict do have to abide by international law obligations; first of all to respect the sanctity of civilians life, but also the inviolability of UN property and premises" he added.
