The attack occurred during morning prayer on Saturday.
There were people praying, people washing themselves, and there were people sleeping on the upper floor, including children, women, and elderly people, said witness Abu Anas.
The reports of the number of deaths vary: rescue teams in Gaza City, controlled by the terrorist-stamped Hamas, claimed that 93 people were killed.
"It can now be confirmed that at least 19 Hamas and Islamic Jihad terrorists were eliminated," reads a statement from Israel's military (IDF). The military also lists the names of the dead.
"Precision ammunition"
About 20 high-ranking military officials within Hamas and Islamic Jihad were present in the school, according to the IDF, which claims that Hamas has exaggerated the number of dead in the attack.
According to the IDF, these operated from Hamas' command center, which was located in the building, and planned attacks against Israel and its security forces.
"The attack was carried out with three loads of precision ammunition," continues the IDF, claiming simultaneously that "no serious damage was done to the building where the terrorists were hiding."
The reports have not been confirmed by independent media or organizations.
The school was a shelter for many internally displaced people who were forced to leave their homes in the war between Hamas and Israel.
USA demands details
The Israeli attack is condemned by several countries close to Israel.
The White House says it is "deeply concerned" about the civilian deaths in the attack on a school building in Gaza City.
The deputy spokesperson for the US National Security Council, Sean Savett, writes in a statement that the USA "requests further details" about the incident.
British Foreign Minister David Lammy wrote on X that he was "appalled" by the Israeli attack. Lammy demands "an immediate ceasefire" in Gaza.
EU: No excuse
France's Foreign Ministry also condemned the attack in strong terms:
"For several weeks, school buildings have been attacked repeatedly – with a painfully high number of civilian casualties."
EU Foreign Minister Josep Borrell says he is "horrified".
"At least ten schools have been targeted in recent weeks. There is no excuse for these massacres," Borrell wrote on X.
According to the UN, at least 477 of 564 schools in Gaza have been attacked and damaged since the war broke out. In June, at least 33 people were killed in an Israeli attack on a school in central Gaza.
Israel has blamed civilian deaths in Gaza on Hamas, saying that the extremist group endangers ordinary Gazans' lives by using schools and residential areas as bases for operations and attacks.
The Islamist extremist group Hamas attacked Israel on Saturday morning, October 7, last year. Around 1,150 people are estimated to have fallen victim to the terror attack, most of them civilians, and more than 200 people were taken hostage.
Israel responded by declaring war and has besieged Gaza, bombed the strip continuously, and sent in ground forces with the stated aim of eliminating the terrorist-stamped Hamas.
According to Hamas-controlled authorities, more than 39,600 people have been killed in Israeli attacks in Gaza since the outbreak of war. Large parts of the area's buildings have been razed to the ground, and aid organizations are warning of severe famine.
More than 100 people are still being held hostage in Gaza, according to Israel, since around the same number were released in exchanges and several others were rescued. Many of those still held are feared to no longer be alive.
