The agency highlighted that ongoing Israeli restrictions to humanitarian access have led to desperate levels of hunger in Gaza.
“UNRWA teams work tirelessly to reach families with aid, but the situation is catastrophic,” the statement added.
UNICEF spokesperson James Elder described the difficulties in both delivering aid to Gaza and distributing it within the war-torn coastal enclave.
“More aid workers have been killed in this war than any war since the advent of the UN,” Elder told Al Jazeera.
On Wednesday, UNICEF attempted to transport a truckload of nutritional and medical supplies for 10,000 children from Deir el-Balah to Gaza City, a round trip of 40 kilometers (25 miles), Elder recounted.
“It took 13 hours and we spent eight of those around checkpoints, arguing around paperwork – ‘was it a truck or a van’,” he said.
“The reality is this truck was denied access. Those 10,000 children did not get that aid … Israel as the occupying power has the legal responsibility to facilitate that aid,” Elder stated.
One of the main land crossings in Rafah has been closed since Israeli forces seized the area early last month, heightening fears of famine in southern and central Gaza.
For months, right-wing Israelis have been protesting and blocking roads to prevent aid shipments from reaching Gaza, further straining the flow of desperately needed assistance to the territory.
On Friday, the United States imposed sanctions on a “violent extremist” Israeli group for obstructing and damaging humanitarian aid convoys to Gaza.
The Group of Seven leaders also emphasized that UN agencies must work unhindered in Gaza.
UNRWA, which coordinates nearly all aid to Gaza, has been in crisis since January when Israel accused about a dozen of its 13,000 Gaza employees of involvement in the October 7 attack on Israel.
This accusation led some nations to abruptly suspend funding to the agency, jeopardizing its efforts to deliver aid.
UNRWA chief Philippe Lazzarini has repeatedly condemned Israeli moves leading to the suspension of funding as “additional collective punishment” for Palestinians already suffering from relentless Israeli bombardment.