Thirty-one premature babies were evacuated from Gaza's biggest hospital Sunday, the World Health Organization said, seeking to get the last patients and staff out of what it has dubbed a "death zone".

The evacuation came as Israel, which said it was stepping up military operations against Hamas militants, announced it had found a 55-metre tunnel under the Al-Shifa hospital and released footage it said showed "hostages" inside the facility.

When rocket sirens echo on the factory floor of Rav-Bariach Industries, Israel's biggest maker of security doors, workers rush to take refuge in bomb shelters fitted with their own kit.

As the wailing subsides, they get back to the production line, making more blast-proof safe room hatches as Israel's economy adapts to the uneasy rhythm of life in wartime.

"This is part of our reality," said CEO Idan Zu-Aretz in Ashkelon, 10 kilometres (six miles) from the Gaza Strip where combat rages between Israel and Hamas.

As the war in Gaza continues to hold public attention, Iran is gearing up for parliamentary elections next year where many conservatives are determined to tighten their grip on power.

The Islamic republic has since August opened registration for candidacy in the upcoming parliamentary elections slated for March 1, 2024.

Last week, officials announced that out of the 24,982 applicants, around 28 percent have been disqualified in an initial screening phase.

Columns of Palestinians, some sick, some wounded made their way out of Gaza's largest hospital Saturday, walking for hours through the debris of war as they sought a new refuge.

The Al-Shifa hospital in Gaza City had been the focus of an Israeli special forces operation for days, searching for the Hamas command centre Israel insists is concealed beneath. Both the militants and hospital managers deny any such base exists.

Gaza and the West Bank should eventually be "reunited" under a new Palestinian Authority, US President Joe Biden said in an opinion piece Saturday, as questions swirl over the future of the region once Israel achieves its goal of crushing the Hamas militant group.

"As we strive for peace, Gaza and the West Bank should be reunited under a single governance structure, ultimately under a revitalized Palestinian Authority, as we all work toward a two-state solution," Biden wrote in the piece published in The Washington Post.

Clutching photos of their missing loved ones, hundreds of relatives of hostages snatched into Gaza on October 7 marched into Jerusalem on Saturday to demand answers from the Israeli government.

The families, their faces etched with exhaustion and stress, were joined by thousands of supporters on the march which set out Tuesday from the coastal city of Tel Aviv, urging action to bring to the release of captives.

Clutching a blown-up surgical glove as a makeshift toy, a Palestinian child is stretchered onto a plane to Abu Dhabi -– one of the Gaza war's first evacuees to the United Arab Emirates for urgent medical treatment.

In the dead of night at Egypt's El Arish airport, near the Rafah border crossing from Gaza, the child is carried carefully from the back of one of six yellow ambulances waiting near the runway, blue lights flashing.

In a ramshackle Palestinian refugee camp in Lebanon, Hayat Shehadeh wrings her hands as she watches the Israel-Hamas war. Her daughter is in Gaza, and she has not spoken to her for a week.

"I can't sleep. I get up at 3:00 am... I go to watch the television," said the 69-year-old from her dark flat in south Beirut's Burj al-Barajneh Palestinian camp.

"Sometimes she writes to me, 'I'm fine'. She doesn't write more than that" because she has no way to recharge her phone battery, said the elderly woman, a baby grandchild playing with a Palestinian flag on the floor nearby.

Gaza's largest hospital has become a "death zone," the World Health Organization said Sunday, announcing plans to evacuate the facility, as Israel's army said it was expanding operations to destroy Hamas.

The assessment came after a visit by WHO and other UN officials to the hospital, which Israeli troops raided earlier this week.

Elsewhere, a Hamas health official said more than 80 people were killed Saturday in twin strikes on a northern Gaza refugee camp, including on a UN school sheltering displaced people.

When Hamas militants stormed Omer Weiss' kibbutz in southern Israel on October 7, they killed his father and kidnapped his mother. On Thursday the Israeli military told him she had been found dead, and his world fell apart again.

Yehudit Weiss, 65, was one of some 240 hostages snatched by militants and taken to the Gaza Strip, according to Israeli authorities.

With their home in kibbutz Beeri devastated in the attack, Weiss and his wife and baby daughter have been staying with friends in the coastal city of Netanya.