Children play among tents pitched on UN premises in Khan Yunis where their parents hope there may be some refuge from Israel's retaliatory bombardment of the Hamas-ruled Gaza Strip
Israeli war planes have levelled entire city blocks in Gaza in preparation for a ground invasion they say is coming soon. AFP

Trucks stuffed with international aid for Gaza should be rolling "in the next day or so," the United Nations said Friday, with Palestinians desperate for life-saving supplies after relentless bombing from Israel, still reeling from its bloodiest-ever attack.

Israel has vowed to destroy Hamas after the Islamist militant group launched an unprecedented raid from the Gaza Strip on October 7, killing at least 1,400 people, mostly civilians who were shot, mutilated or burned to death, according to Israeli officials.

Hamas gunmen also kidnapped nearly 200 hostages including foreigners from around two dozen countries ranging from Paraguay to Tanzania.

In response, Israeli war planes have levelled entire city blocks in Gaza in preparation for a ground invasion they say is coming soon. More than 3,785 Palestinians, mostly civilians, have died in the bombing, according to the latest toll from the Hamas-run health ministry.

The United Nations says more than one million of Gaza's 2.4 million people are displaced and that the humanitarian situation is deteriorating daily.

A spokesman for UN humanitarian chief Martin Griffiths told reporters in Geneva they were in "deep and advanced negotiations" with all sides to ensure aid moves "as quickly as possible."

"A first delivery is due to start in the next day or so."

Medicine, water purifiers and blankets were being unloaded at El Arish airport near Gaza, an AFP reporter saw, with Ahmed Ali, head of the Egyptian Red Crescent, saying he was getting "two to three planes of aid a day".

The situation inside Gaza is "beyond catastrophic", said Sara Alzawqari, UNICEF spokeswoman for the Gulf. "Time is running out and the numbers of casualties amongst children are rising."

Egyptian state-linked broadcaster Al Qahera News had said the Rafah crossing -- the only route into Gaza -- would open Friday, but Cairo has said it needed more time to repair roads.

Raising some hope aid could soon flow, Egypt has removed concrete blocks on the only route into Gaza, a security source told AFP.

Egypt is still fixing bomb-damaged roads and on Friday "vehicles and Egyptian equipment went in to repair the road on the Palestinian side", witnesses told AFP.

The World Health Organization's emergencies director has called a deal struck by US President Joe Biden to allow in 20 trucks "a drop in the ocean of need".

"It should be 2,000 trucks," said Michael Ryan.

Within Israel, still coming to terms with the deadliest attack in its 75-year history, the drumbeat of war was growing louder, as leaders rallied troops for a ground offensive.

Clad in body armour, Israel's Prime Minister Benjamin Netanyahu embraced front-line troops near Gaza, urging them to "fight like lions" and "win with full force".

Fists clenched and voice raised, Netanyahu told cheering soldiers: "We will deal harsh blows to our enemies in order to achieve victory."

Defence Minister Yoav Gallant also toured the front line, telling some of the tens of thousands of troops awaiting the ground invasion that "the order will come soon."

"Right now you see Gaza from afar, soon you will see it from the inside," said Gallant.

Israeli jets struck more than 100 Hamas targets overnight, killing at least one Hamas operative, the army said Friday.

The horror of what Israel suffered on October 7 and following days was still emerging, as traumatised residents recounted their stories.

Shachar Butler, a security chief at the Nir Oz kibbutz, where Hamas militants killed or kidnapped a quarter of the 400 residents, recalls more than a dozen gunmen spraying bullets indiscriminately and lobbing grenades at homes.

"It's unimaginable," the 40-year-old told AFP as part of a trip organised by the Israeli military.

"Anytime someone tried to touch my window, I shot him," he said. "The people who came out got kidnapped, killed, executed, slaughtered."

Butler estimated as many as 200 militants attacked the kibbutz, entering from three sides before going house-to-house. Homes there were still charred with burned personal belongings strewn everywhere.

Israel says around 1,500 Hamas fighters were killed in clashes before its army regained control of the areas under attack.

During a rare address from the Oval Office, Biden urged the United States to take the lead in supporting Israel and Ukraine, saying he would make an "urgent" request to Congress for aid later Friday.

"American leadership is what holds the world together," Biden said in just his second primetime speech from behind the historic Resolute Desk.

Fresh from a whirlwind trip to Israel this week, Biden is hoping to staunch the possibility of a wider Middle East war.

The United States has already moved two aircraft carriers into the eastern Mediterranean to deter Iran or Lebanon's Hezbollah, both allies of Hamas, from getting involved.

But fears of a wider conflagration are growing, with Israel announcing plans to evacuate the northern city of Kiryat Shmona after days of clashes with Hezbollah fighters along the border with Lebanon.

Meanwhile, Gaza students in Egypt told AFP of their nightmare watching events unfold from far away.

Haya Shehab, 21, learned from an Instagram post that her extended family's home had been bombed, killing 45 people -- dozens of them cousins.

"Just like that, 45 of us gone," said Shehab, who studies at a private university in Cairo.