Tens of thousands of Palestinians scrambled to flee northern Gaza on foot Wednesday after Israel’s military gave them a four-hour window to leave. Israeli officials say some 100,000 civilians remain in northern Gaza, down from more than a million a month ago. Human rights groups say many seniors, pregnant people, parents of young children and people with disabilities have been unable to heed Israel’s mass evacuation orders. This is Ahmed Mohammed, whose neighborhood near the al-Shati refugee camp came under intense Israeli bombardment.

Ahmed Mohammed: “May Allah protect us, because under these circumstances, anyone who wants to leave needs to have enough resources to be able to do that. Those without will have to stay where they are. It’s as if they’ve sentenced us to death.”

The U.N. agency for Palestinian refugees, UNRWA, says 70% of Gaza’s residents are displaced. Supermarkets have been swept clean of food and other essentials, and Israeli assaults have destroyed about a dozen of Gaza’s bakeries. With no clean drinking water, Palestinians have been forced to bathe in the Mediterranean Sea, where a total shutdown of Gaza’s wastewater treatment plants has forced the daily release of huge quantities of untreated sewage. The World Health Organization warned Wednesday of the spread of disease; it says since early October there’s been a sixteenfold increase in cases of diarrhea, most of them children under 5.

Gaza’s Health Ministry says one Palestinian child is being killed every 10 minutes, as 4,324 children have been confirmed killed in 33 days of relentless bombardment. Another 1,350 children are missing and presumed buried under the rubble. More than 10,500 Gazans have been killed.

On Wednesday, United Nations High Commissioner for Human Rights Volker Türk traveled to the Egyptian side of the Rafah border crossing to Gaza, where he demanded an immediate ceasefire and accused both Israel and Hamas of committing war crimes.

Volker Türk: “This is the gateway to a hellish nightmare. I cannot even fathom to think what people are going through on the other side. And then I see in front of me the lifeline that would bring — that would bring relief and humanitarian assistance, which until now has not been enough, woefully inadequate.”

Click here to see our interview with Volker Türk, as well as the head of the New York Office of the U.N. High Commissioner for Human Rights who resigned in protest over Israel’s assault on Gaza.