Alarm grew for Palestinian civilians trapped in the devastating Gaza war as the UN's top court was set to hand down an initial ruling Friday in a case accusing Israel of genocide.

The International Court of Justice (ICJ) could order Israel to halt its military campaign launched in retaliation for Hamas's unprecedented attacks on October 7, although it has little power to enforce its rulings.

A growing chorus of international voices has expressed concern for the civilian population of Khan Yunis, the main city in Gaza's south, and elsewhere in the besieged territory.

In scenes of desperation, AFPTV footage showed hundreds of Palestinians crowding around a truck delivering humanitarian aid, many clinging onto its roof, in Gaza City.

The health ministry in Hamas-run Gaza said 20 people were killed and 150 wounded on the city's outskirts on Thursday while they waited for aid to be distributed.

"Suddenly, tanks appeared and started firing shells at the people, who were cut into pieces," said Abu Ata Basal, the uncle of one of the wounded.

Bodies were seen lying on the floor of Al-Shifa hospital in Gaza City.

Hamas, the Islamist movement running the Gaza Strip, charged the attack amounted to a "horrific war crime". Palestinian militant group Islamic Jihad said it was caused by "artillery shells and missiles".

AFP was unable to verify those claims independently, and the Israeli military had yet to respond to a request for comment.

US media meanwhile reported that the US, Israeli and Egyptian spy chiefs would soon meet in Europe, joined by the Qatari prime minister, in a bid for a Gaza truce and hostage release.

- Israel evacuation order -

The Gaza City strike came a day after the United Nations said tanks had shelled one of its shelters in Khan Yunis, killing 13 people.

The UN agency for Palestinian refugees (UNRWA) said the Israeli army had ordered people sheltering at the site to leave at 5:00 pm (1500 GMT) on Friday, although the Israeli military denied issuing a specific evacuation request.

France called on Israel to "comply with international law" and joined the United States in condemning the Khan Yunis strike, although it did not directly identify Israel as responsible.

The Israeli military is the only force known to operate tanks in Gaza.

Hamas also reported fierce clashes in the centre and west of Khan Yunis, the hometown of Hamas's Gaza chief Yahya Sinwar, the suspected mastermind of the October 7 attacks.

The Hamas attack resulted in about 1,140 deaths in Israel, mostly civilians, according to an AFP tally of official Israeli figures.

Militants also seized about 250 hostages and Israel says around 132 of them remain in Gaza, including the bodies of at least 28 dead captives.

Israel has vowed to crush Hamas and launched a military offensive that Gaza's health ministry says has killed at least 26,083 people, about 70 percent of them women and children.

The Israeli army said Friday one more soldier had died in Gaza, bringing the total to 220 since ground operations started in late October.

- Urban combat -

Israel's military said several militants were killed in "close-quarters combat" in Khan Yunis and weapons including rifles, grenades and mortar shells were seized.

An AFP journalist said the bombardment was incessant on Thursday in Khan Yunis, where the Israeli military says the Hamas leadership is in hiding.

The Gaza health ministry said 120 people were killed across Gaza overnight.

Many thousands have fled the city to seek refuge in Rafah, further south on the Egyptian border, where most of the 1.7 million Palestinians displaced by the war have gathered.

They piled their belongings into cars, tractors and donkey-drawn carts while many others fled on foot.

"I don't know where I'm heading," said Musa Abu Yussef. "I've taken nothing with me, no blankets, no sheets, no (tent) -- nothing at all."

- 'Sea of people' -

UNRWA head Philippe Lazzarini said on social media platform X that "a sea of people" had been forced to flee Khan Yunis for the border with Egypt.

An AFP journalist in Rafah said there was no more space left for the tens of thousands escaping Khan Yunis and that fears were growing about Israeli troops reaching Rafah.

South Africa lodged an application with the ICJ last month arguing Israel was violating the UN Convention on Genocide and seeking urgent measures to protect Gazans.

While the ICJ's decision on that application is due at 1:00 pm (1200 GMT) on Friday, a judgement on whether or not Israel is committing genocide in Gaza could take years.

The case has sparked fury in Israel, with Prime Minister Benjamin Netanyahu vowing that "no one will stop us".

Hamas pledged on Thursday to respect a ceasefire if called upon by the Hague tribunal, on condition that Israel also complies.

Israeli flag carrier El Al said Friday it will scrap direct flights to South Africa following "a significant fall in demand by Israeli travellers".

US media reported late on Thursday that CIA director William Burns would travel to Europe soon to meet his Israeli and Egyptian counterparts, as well as the Qatari prime minister, in a bid to negotiate another Gaza truce and the release of hostages.

The New York Times and Washington Post quoted unidentified officials as saying Burns would seek to launch a new round of talks, although the US intelligence agency and the White House declined to confirm his travel plans.

Under a week-long truce in November, about 100 hostages were freed by Hamas in exchange for 240 Palestinian prisoners held by Israel.

US President Joe Biden's Middle East envoy Brett McGurk is already in the region for talks.