Salma Saud was sleeping in the Ahmed bin Abdul Aziz School in Khan Younis when rubble and debris fell on top of her.

"I felt fear and thought maybe this is it," the 19-year-old told CBC News.

The rubble was from an Israeli strike on the United Nations-run school. At least 20 displaced Palestinians sheltering in the building were killed when Israel bombarded the building without warning, survivors said. 

"My sister lost consciousness … [and] my mother, as soon as I removed the rubble I knew she was martyred," Saud said.

"I lost my father before today … and today I lost my mother."

Survivors say the strike hit the building at around 9:30 p.m. Many there, including 30-year-old Khitam Al-Tarawsa, were taking refuge in the school after Israeli attacks forced them to flee several times. 

"The children were in a panic, and even us, the adults, we were in a panic," she said. "We started running in the middle of the night and found three or four classrooms fallen on top of each other and there were martyrs."

The strike was one of several Israeli weekend attacks across the besieged territory, including in Beit Hanoon and Deir el-Balah.

Elsewhere, an airstrike hit the civil emergency centre in the Nuseirat market area in the central Gaza Strip, killing Ahmed Al-Louh, a video journalist for Al Jazeera TV, and five other people, medics and fellow journalists said. 

Another strike on a house in the Nuseirat camp killed five people, including children, according to medics.

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The Israeli military said it targeted sites used by Hamas and Islamic Jihad militants operating from Gaza's Civil Defence's Nuseirat office. But those hit by the strikes contest that the vast majority of those killed were women and children.

"We were just sitting in our homes, innocent people in their space. Suddenly, they saw the bomb landing in the middle of the room," said Khaldiya Tafesh, who lost her son and seven grandchildren to the strike on the UN school.

"There wasn't anyone wanted or anything."

'I lost everyone'

Al-Tarawsa and her family were displaced to the Nasser Hospital after the Israeli attack, but they returned to the school in the morning to assess the damage. 

She said everything was destroyed, "nothing is in one piece, no furniture left."

Survivors say Israel didn't warn them prior to the attack, so many of those in the building were asleep when the bomb hit.

"The bomb came down and we don't know from where or who was affected," said Al-Tarawsa. "Until now, our heads hurt."

The attack left a bloody scene for the survivors and medical personnel. Al-Tarawsa says shrapnel from the attack hit her and her children, who were sitting near the site of the bombing.

Elsewhere in the building, 23-year-old Bisan Azdoudi says she saw the brains of loved ones fly out of the heads.

"I lost my uncle, I lost everyone. No one is left for me," she said.  "I tried to get my brothers and sisters out from under the rubble. No one is left."

Sharif Awda says they were taking women and children in pieces to the hospital, as the strike and its impact had cut them apart.

"We never imagined they would strike this school," he said. "If you were to strike an UNRWA school you should warn them."

Death toll more than 45,000: Health Ministry

Gaza's Health Ministry updated the death toll to 45,028 people on Monday, with 106,962 others injured since the start of the war.

The official toll amounts to about two per cent of Gaza's entire pre-war population of 2.3 million — though officials say the real toll is higher because thousands of bodies are still buried under rubble or in areas medics can't access.

Israel claims Hamas is responsible for the civilian death toll because it operates from within civilian areas in the densely populated Gaza Strip, but rights groups and Palestinians say Israel has failed to take sufficient precautions to avoid civilian deaths.

The Israeli military says it has killed more than 17,000 militants, without providing evidence. The Gaza Health Ministry does not distinguish between civilians and combatants in its count, but it has said that more than half of the fatalities are women and children. 

Furthermore, UN agencies, the International Committee of the Red Cross and even the United States have used the Health Ministry's numbers in the past.

With the death toll mounting ever higher, efforts to reach a ceasefire have picked up in recent weeks after repeatedly faltering. Qatar, Egypt and the U.S. have renewed their efforts to broker a deal at senior levels in recent days. Mediators have said there appears to be more willingness from both sides to conclude a ceasefire.

Al-Tarawsa says she has no energy left to deal with Israel's constant attacks, which have been ongoing since Hamas militants stormed into Israel on Oct. 7, 2023. Israel says that attack killed about 1,200 people in Israel and that about 240 hostages were taken back to Gaza.

"We're tired of the bombings and the war," Al-Tarawsa said.

"We live here, yes, but there's no safety. We live between walls, no door is safe, no window is safe. Nothing is safe."