A UN spokesman said on Tuesday that more than 160 school buildings have so far been hit in the Gaza Strip, where Israeli attacks continue.
"Humanitarian colleagues working on education have analyzed satellite images to assess damage to schools across Gaza.
"Their assessment found that 162 school buildings have been directly hit, representing nearly 30% of the total 563 school buildings in Gaza," Stephane Dujarric told reporters in New York.
At least 26 of these buildings have been destroyed, he added.
"Some 175,000 students and more than 6,500 teachers have had their schools directly hit in hostilities. At least 55% of schools in Gaza will require either full reconstruction or major rehabilitation," Dujarric said.
Asked whether Israel is "intentionally" blocking the humanitarian aid in Gaza, Dujarric said the delivery of humanitarian goods is "woefully inadequate" because of circumstances that are way beyond the control of the UN.
"It's been very difficult to get the volume that we need through Kareem Shalom (crossing) ...," he said, adding there have also been issues with the safety of trucks and personnel once they cross into the enclave.
"It's been very challenging to get deliveries going outside of Rafah north because as far as I'm told the de-conflicting mechanism that we have with the Israeli authorities which to ensure the safety of our convoys, has not been working as it should, if working at all," he said.
Aid delivery is being done "piecemeal in an opportunistic way, which is frankly no way to run a humanitarian operation."
Dujarric said Secretary-General Antonio Guterres made his position "very clear," and called on all those who have an influence on the parties to use that influence to stop the carnage, to ensure the humanitarian aid gets in, to ensure that all the hostages get released.
On a question that why Guterres is not calling on countries to stop their arms delivery to Israel, Dujarric said: "What is clear to us is that all of the money spent on weapons throughout the world fueling conflict in many parts of the world would be better spent on development and on the well-being of people."
Israel has pounded the Gaza Strip since an Oct. 7 Hamas attack, killing at least 28,473 victims and injuring 68,146. About 1,200 Israelis are believed to have been killed in the initial Hamas attack.
The Israeli war on Gaza has pushed 85% of the territory's population into internal displacement amid acute shortages of food, clean water and medicine, while 60% of the enclave's infrastructure has been damaged or destroyed, according to the UN.
