A projectile struck a complex containing a UN school in Beit Hanun in northern Gaza on Thursday, killing at least 15 people and wounding dozens more, according to Palestinian medical sources.
The school had served as a shelter for internally displaced Gazans.
The IDF launched an investigation, and army sources said it was unclear whether the area was hit by an Israeli or Palestinian range projectile.
Later Thursday night, the IDF said an initial investigation found that terrorists had opened fire from the vicinity of the school, and that the army returned fire. At the same time, Hamas fired in the general direction of the school, the army said. Civilians in the school were asked to vacate the area, but refused, the army added.
“I am appalled by the news of an attack on an UNRWA school in northern Gaza taken refuge,” UN Secretary-General Ban Ki-Moon said on Thursday.
The school was closed for the summer but was used to help civilian refugees from the fighting.
In Washington, US State Department spokeswoman Jen Psaki said the attack on the school “underscores the need to end the violence and to achieve a sustainable cease-fire and enduring resolution of the crisis in Gaza as soon as possible.” She added: “We again urge all parties to redouble their efforts to protect civilians.”
Both Ban and his spokesman Farhan Haq said they still did not know who attacked the school.
“Circumstances are still unclear. I strongly condemn this act,” Ban said. The attack occurred while UNRWA staff attempted to arrange a “humanitarian pause” in the violence in that area, so civilians could be evacuated, Ban said.
UNRWA spokesman Chris Gunness said his organization had provided Israel with the precise coordinates of the school, which was marked with a UN flag.
“We were trying to negotiate with the IDF,” so that it would be safe for civilians to leave the area, Gunness said. “We tried and tried but the approval never came.”
Many people, including women and children, were killed in the attack, Ban said.
“I express my profound condolences to the families of the victims and those of so many hundreds of innocent Gazans who have tragically been killed as a result of the massive Israeli assault,” he said.
Ban said it was important to ensure that UN facilities were not drawn into the conflict, either by Israel or Hamas. He urged Israel to take precautions to insure that they did not attack places where civilians had taken refuge.
Since the conflict began 16 days ago, he said, 100,000 people in Gaza, 5% of its population, had sought refugee in UNRWA facilities.
Ban stressed that “all sides...must abide by their obligations under international humanitarian law to respect the sanctity of civilian life, the inviolability of UN premises and to honor their obligations to humanitarian workers.”
“Today’s attack underscores the imperative for the killing to stop – and to stop now,” Ban said.
The attack on the school comes in the aftermath of UNRWA reports that two of its schools, which were closed for the summer, were used to store weapons.
UNRWA handed 20 rockets found in one school over to representatives of the national consensus government, which Hamas has disavowed. But it was harshly criticized for doing so, because it is believed that all such authorities are under Hamas’s control.
This week, UNRWA found a weapons cache in a school, where civilians were close by. It evacuated the area, but when the staff returned the next day, the weapons were gone.
The UN is creating new procedures to handle such a situation so that its organization can deal with the weapons disposal.
Haq said Ban was alarmed and outraged to hear of the rockets placed in UNRWA schools that have subsequently gone missing.
Separately, according to Gunness, the IDF had hit two UNRWA schools during Operation Protective Edge.
Since the start of the ground offensive in Gaza last week, the IDF has uncovered 31 tunnels and destroyed 11, including cross-border passages that surfaced in Israel, signifying that the first goal of the ground offensive is close to being realized.
The Paratroopers Brigade uncovered 32 tunnel shafts and killed 72 terrorists across Gaza since last Thursday. It arrested 15 suspects on Thursday, who are being questioned, and destroyed two tunnels since entering the Gaza Strip.
On Thursday morning, paratroopers detected two terrorists who emerged from a tunnel shaft. They were captured and taken into custody for questioning.
Paratroopers also saw a terrorist approaching them in southern Gaza wearing explosives. Soldiers opened fire and struck the man.
Minutes later, the unit discovered two tunnel shafts nearby.
Such battles are a sign that Hamas is continuing to try to fend off and delay the IDF’s work to demolish the tunnel network, without success.
The IDF took some 150 security suspects into custody on Thursday morning in Gaza and led them to Israel. After questioning, dozens were released, and some 80 were taken by Military Police to a facility in southern Israel for further questions. Most of the suspects gave themselves up to security forces.
In a clear signal to Hamas’s leadership, the IAF struck the home of senior Hamas member Mahmoud al-Azhar on Thursday. Al-Azhar is one of the founding members of Hamas, and has served as a ‘foreign minister’ for it since Hamas seized power in Gaza.
Meanwhile, heavy battles continued to occur across the Strip.
Terrorists in Gaza fired an antitank missile at the IDF from al-Wafa hospital on Thursday, using the structure as an attack base, despite Israel’s air strike on the structure on Wednesday following previous gunfire and missiles fired from it by Hamas.
The IDF fired back, killing two terrorists, and the air force later struck the building from which the missile was fired. The air force also struck a structure near al-Wafa hospital used to store weapons, which was used as a command and control center.
The IDF struck 90 targets in Gaza over the past 24 hours, the army said Thursday afternoon.
Targets included underground rocket launchers, terrorist lookout points, and other infrastructure used to facilitate projectile attacks on Israel. An Armored Corps unit detected gunmen in its vicinity, and fired shells at it, striking the terror suspects.
Reuters contributed to this report.