Health officials in Hamas-run Gaza reported on Monday more than 24,000 deaths in the attack by Israel which has sent shockwaves across the region, as the offensive passed the grim 100-day milestone.

Deadly violence in the Israeli-occupied West Bank and along Israel's border with Lebanon as well as fighting between US forces and Iran-backed Yemeni rebels in the Red Sea have raised fears of an escalation beyond the Gaza Strip, AFP reports.

The attack has created a humanitarian catastrophe for the 2.4 million people in the besieged strip, the United Nations and aid groups warn, and reduced much of the territory to rubble.

The health ministry in Gaza, ruled by Hamas since 2007, reported more than 60 "martyrs" and dozens more wounded overnight, in what the group's media office described as "intense" Israeli bombardment across Gaza.

The Hamas government media office said two hospitals, a girls' school and "dozens" of homes were hit overnight.

Hospitals in Gaza have been hit repeatedly since October 7, and the World Health Organization (WHO) says most of them are no longer functioning.

The Israeli military accuses Hamas of operating out of civilian facilities or from tunnels under them, a charge the Islamist group denies.

The latest strikes hit the southern cities of Khan Yunis and Rafah, as well as areas around Gaza City, the Hamas media office said.

The army said its forces had struck "two terrorists loading weapons into a vehicle" in Khan Yunis, southern Gaza's main city, and raided "a Hamas command centre" there and seized weapons.

The UN says more than three months of fighting have displaced roughly 85 percent of the territory's population, crowded into shelters and struggling to get food, water, fuel and medical care.

"There's no food, no water, no heating. We are dying from the cold," said Mohammad Kahil, displaced from northern Gaza to Rafah, on the southern border with Egypt.

'Living in hell'

Vowing to destroy Hamas, Israel launched a relentless military campaign that has killed at least 24,100 people in Gaza, mostly women and children, according to the territory's health ministry.

WHO chief Tedros Adhanom Ghebreyesus has said people in Gaza were "living in hell", echoing earlier UN warnings of a fast-approaching famine.

In a joint statement on Sunday, the WHO, World Food Programme (WFP) and UNICEF said "a fundamental step change in the flow of humanitarian aid into Gaza is urgently needed".

They called for "safer, faster" supply routes to be opened, warning that the current levels of aid "fall far short of what is needed to prevent a deadly combination of hunger, malnutrition and disease".

The WFP said an aid convoy brought food to the territory's north on Thursday, the first such delivery since a one-week truce ended on December 1.

Cindy McCain, the UN agency's director, said: "People in Gaza risk dying of hunger just miles from trucks filled with food. Every hour puts countless lives at risk."

Israel has faced international pressure over surging civilian casualties in Gaza, and Prime Minister Benjamin Netanyahu is under intense domestic pressure to account for political and security failings surrounding the October 7 attacks.