Israel has pounded Gaza with more air strikes, as British Prime Minister Rishi Sunak followed US President Joe Biden on visits to demonstrate support for war against Hamas while urging Israel to ease the plight of besieged Gazans.

Biden, who spent less than eight hours in Israel, flew home on Wednesday night having pledged support, and hugged and consoled survivors of the October 7 raid by Hamas gunmen who rampaged through southern Israel, killing 1400 people.

But he appeared to have only limited success in his other mission, to persuade Israel to ease the plight of 2.3 million Gazans under a total siege.

Biden said he had secured an offer from Egypt to allow 20 aid trucks to reach Gaza at some point in coming days, a fraction of the 100 per day that UN aid chief Martin Griffiths told the Security Council were needed.

Inside Gaza there was no let-up of the punishing Israeli bombardment that health officials say has so far killed nearly 3500 people and wounded more than 12,000.

The United Nations says around half of Gazans have been made homeless, still trapped inside the enclave, one of the most densely populated places on earth.

In Khan Younis, in the south of the Gaza Strip, an area of shops was reduced to rubble as far as the eye could see, with a toddler’s pink cot overturned on the ground, windows blown off a clothing store and damaged vehicles.

Rafat Al-Nakhala, who had sought shelter in there after obeying Israel’s order for civilians to flee Gaza City in the north, said nowhere was safe.

“I’m over 70 years old, I’ve lived through several wars, it’s never been like this, it has never been this brutal, no religion and no conscience. Thank God. We only have hope in God, not in any Arab or Muslim country or anyone in the world, except for God.”

Footage obtained by Reuters from the Jabaliya refugee camp in the north showed residents digging with their bare hands inside a damaged building to free a small boy and girl trapped under masonry. The body of a man was hauled out of the ruins on a stretcher as residents tried to light up the site with torches on their mobile phones.

The plight of Gaza civilians has enraged the Middle East, making it more difficult for Biden and other Western leaders to rally Arab allies to prevent the war from spreading.

An explosion at a hospital in Gaza on the eve of Biden’s visit scuppered his plans to meet Arab leaders, who called off a summit with him. Palestinians blamed the explosion on an Israeli air strike and said it killed nearly 500 people. Israel said it was caused by a failed rocket launch by Palestinian fighters.

Angry demonstrations erupted in cities throughout the region. Biden said US evidence supported the Israeli account of the hospital explosion.

Israel said it would allow limited aid to reach Gaza from Egypt provided none of it benefited Hamas. But it repeated its position that it will open its own checkpoints to let in aid only when all of the more than 200 hostages captured by the gunmen were set free.

Instead of meeting in person, Biden spoke to Egypt’s President Abdel Fattah al-Sisi by phone from Air Force One on his flight back to Washington.

Egypt has long said its crossing to Gaza is open on its side but aid cannot get through due to Israeli bombardment of the Gaza side. Cairo has also firmly rejected any suggestion that it open the border to allow a mass exodus of Gazans to flee to safety.

Sunak landed in Tel Aviv on Thursday, hours after Biden left, carrying similar messages of support and condolence for Israelis.

“Above all, I’m here to express my solidarity with the Israeli people. You have suffered an unspeakable, horrific act of terrorism and I want you to know that the United Kingdom and I stand with you,” Sunak told Israeli reporters after landing.

–with AAP