A convoy of more than 100 UN aid lorries carrying food was violently looted in Gaza on Saturday, the UN agency for Palestinian refugees (Unrwa) says.

Ninety-seven lorries were lost and their drivers were forced at gunpoint to unload their aid after passing through the Israeli-controlled Kerem Shalom crossing with southern Gaza, in what is believed to have been one of the worst incidents of its kind.

Eyewitnesses said the convoy was attacked by masked men who threw grenades.

Unrwa commissioner general Philippe Lazzarini did not identify the perpetrators, but he said the “total breakdown of civil order” in Gaza meant it had “become an impossible environment to operate in”.

Without immediate intervention, severe food shortages are set to worsen for the two million people depending on humanitarian aid to survive, according to Unrwa.

A UN-backed assessment warned earlier this month that there was “strong likelihood that famine is imminent in areas within the northern Gaza Strip”.

It came after Israeli forces launched a major ground offensive in the north and the UN said fewer aid lorries had entered Gaza last month than at any time since the start of the war between Israel and Hamas in October 2023.

Saturday’s looting was first reported by Reuters news agency, which cited an Unrwa official in Gaza as saying that the convoy was instructed by Israeli authorities to “depart at short notice via an unfamiliar route” from Kerem Shalom.

Lazzarini said he could not comment on the report when asked at a news conference in Geneva on Monday, but he confirmed the looting and said: “We have been warning a long time ago about the total breakdown of civil order.”

“Until four or five months ago, we still had local capacity, people who were escorting the convoy. This has completely gone, which means we are in an environment where local gangs, local families, are struggling among each other to take control of any business or any activities taking place in the south. It has become an impossible environment to operate in.”

He added that hundreds of people desperate for food had tried to storm the Unrwa-run vocational centre in the southern city of Khan Younis because they thought the aid had been delivered there.

“But the convoys were looted and there was absolutely nothing to take from the warehouses.”

Unrwa put out a separate statement on X that accused Israeli authorities of continuing to “disregard their legal obligations under international law to ensure the population’s basic needs are met and to facilitate the safe delivery of aid”.

“Such responsibilities continue when trucks enter the Gaza Strip, until people are reached with essential assistance.”

Earlier, the Israeli military body responsible for humanitarian affairs in the Gaza Strip, Cogat, said on X: “With the challenges the UN aid organisations experience in distributing aid, we are working together on various measures that will facilitate the transfer of aid from the Kerem Shalom crossing to Gazans in need.”

“For months now, aid has been piling up on the Gazan side, after Israeli inspection, waiting for collection and distribution, and we’ve been taking many measures to assist with the pick-up of aid,” it added.

Israel has previously insisted there are no limits to the amount of aid that can be delivered into and across Gaza, and accused Hamas of stealing aid, which the group has denied.

Last week, a group of 29 non-governmental organisations said in a report that the looting of aid convoys was “a consequence of Israel’s targeting of the remaining police forces in Gaza, scarcity of essential goods, lack of routes and closure of most crossing points, and the subsequent desperation of the population amid these dire conditions”.

They cited media reports as saying that “many incidents are taking place close by or in full view of Israeli forces, without them intervening, even when truck drivers asked for assistance”.

Israel launched a campaign to destroy Hamas in response to the group’s unprecedented attack on southern Israel on 7 October 2023, in which about 1,200 people were killed and 251 others were taken hostage.

More than 43,920 people have been killed in Gaza since then, according to the territory’s Hamas-run health ministry.