More than 50 people were killed in Israeli air and ground attacks across the Gaza Strip on Sunday, according to local medics and rescuers.

They said children, a cameraman working for the Al Jazeera TV network and staff from the Civil Defense agency were among the dead.

The Israeli military said it targeted sites used by Hamas and the Palestinian Islamic Jihad armed group.

The Hamas-run health ministry said the deaths meant the number of Palestinians killed in Gaza during the 14-month war between Israel and Hamas had surpassed 45,000.

The ministry does not distinguish between fighters and civilians, but it reported in October that 29,980 children, women and the elderly were among those killed.

The figures are often disputed by the Israeli government, which says nearly 20,000 "terrorists" have been killed, but are generally accepted by UN agencies.

The war began when gunmen led by Hamas carried out an unprecedented attack on southern Israel on October 7, 2023, during which approximately 1,200 people were killed and 251 others were kidnapped.

Many of those killed Sunday were at a UN-run school being used as a shelter for displaced families in the southern city of Khan Younis.

Harrowing footage showed a bloody scene on the third floor of the Ahmed bin Abdul Aziz School, with the bodies of children apparently among those taken away.

"People were safe, staying in their homes after doing the dinner prayer. They were sitting, sleeping, and staying put," Manal Tafesh, whose brother and children were among those killed, told the Reuters news agency outside a local area. .

Medics said at least 13 people had been killed, and a spokeswoman for the UN agency for Palestine refugees (Unrwa) said she had heard reports of about 20 casualties, many of them women and children.

"That doesn't stop. The pain and the suffering is what we still have," Louise Wateridge told the BBC from central Gaza.

The Israel Defense Forces (IDF) said it had carried out a "detailed strike against Hamas terrorists operating inside a command and control center" embedded in the school.

He also accused Hamas and other armed groups of exploiting civilians and using civilian infrastructure as human shields.

Medics said several more people were killed at another school shelter in the northern town of Beit Hanoun, which the UN said has been under siege by Israeli forces for more than two months.

The UN said it is monitoring reports that more than 1,500 people have been displaced after Israeli forces attacked and destroyed the Khalil Aweida school.

The IDF said on Sunday that its forces carried out a "targeted attack on a terrorist meeting place in the Beit Hanoun area".

"In cooperation with the (Israeli Air Force), the troops hit dozens of terrorists from the air and from the ground, and additional terrorists were captured," he said.

Another strike hit a Civil Defense building in the Nuseirat refugee camp in central Gaza.

Civil Defense spokesman Mahmoud Basal said the strike killed the leaders of their Nuseirat and Sheikh Radwan centers along with two volunteers, one of whom he identified as Ahmad Baker al-Louh. Five others were injured, three of them seriously, he said.

"Israel's occupation has once again shown the world that there is no protection for humanitarian workers in Gaza and no compliance with international humanitarian laws," he said, adding that 94 workers were killed. Civil Defense killed since the start of the war.

Ahmad al-Louh was a cameraman for the Qatar-based Al Jazeera network, which strongly criticized what he called Israel's "targeted killing" of its journalist.

They said Louh had been covering rescue operations with the Civil Defense following a strike earlier on Sunday and that it came "just days after his house was targeted".

"The network calls on all human rights organizations and media to condemn the systematic killing of Israeli workers in cold blood, the evasion of obligations under international humanitarian law, and the perpetrators of this terrible crime bring this to justice," a statement said.

The IDF said the Civil Defense building was used by "terrorists to plan and carry out a terrorist attack against IDF soldiers".

"Among the terrorists killed in the strike was Islamic Jihad terrorist Ahmad Bakr al-Louh, who was previously a platoon commander in the Islamic Jihad Central Camps Group," he said, without giving provided no evidence.

Al Jazeera did not mention the Israeli accusation, however Louh's cousin, Mahmoud, told the Associated Press: "We were surprised by Israel's occupation statement."

"These claims are false and misleading to cover up this crime," he said.

The Committee to Protect Journalists says at least 137 journalists and media workers have been killed in Gaza, the West Bank, Israel and Lebanon since the war began.