“Families are living in classrooms, hallways & makeshift shelters built with plastic,” UNRWA said on X.

It added that living conditions are dire, with scarce resources, insufficient sanitation facilities, very limited supplies, retiterating its call for an immediate ceasefire in Gaza.

On Tuesday, UNRWA said around one million people have fled the Gazan city of Rafah in the past three weeks amid the Israeli military's ongoing incursion.

Before the Rafah offensive began, the United Nations said up to 1.4 million people were sheltering there.

Most of those fleeing Rafah have poured into a humanitarian zone declared by Israel that is centred on Muwasi, a largely barren strip of coastal land.

The zone was expanded north and east to reach the edges of Khan Younis and the central town of Deir Al-Balah, both of which have also been filled with people.

The situation has been worsened by a dramatic plunge in the amount of food, fuel, and other supplies reaching the UN and other aid groups to distribute to the population. Palestinians have largely been on their own to resettle their families and find the basics for survival, AP reported.

“As we can see, there is nothing ‘humanitarian’ about these areas,” said Suze van Meegen, head of operations in Gaza for the Norwegian Refugee Council, which has staff operating in Muwasi.

Much of the humanitarian zone has no charity kitchens or food market, no hospitals operating, only a few field hospitals and even smaller medical tents that cannot handle emergencies, and only pass-out painkillers and antibiotics if they have them, according to testimony from Mercy Corps, as reported by AP.

Meanwhile, humanitarian convoys with supplies for the UN and other aid groups to distribute for free have fallen to nearly their lowest levels in the war, the UN said.

Although the UN was previously receiving several hundred trucks a day, the rate has dropped to an average of 53 trucks daily since 6 May, according to the UN humanitarian office OCHA' latest figures on Friday.

Some 600 trucks a day are needed to stave off starvation, according to the United States Agency for International Development (USAID).

The two main crossings in the south, Rafah from Egypt and Karm Abu Salem from Israel, are either not operating or largely inaccessible for the UN because of the Israeli blockade.