Israel said on Monday it would stop working with UNRWA in Gaza, accusing the aid agency of perpetuating conflict.

The agency said Israel told it that it would no longer approve its food convoys to north Gaza.

Four such requests were denied since March 21, it said.

"The decision must be revoked," OCHA spokesperson Jens Laerke told a UN briefing in Geneva.

"You cannot claim to adhere to these international provisions of law when you block UNRWA food convoys."

UNRWA, which provides aid and services to Palestinian refugees in Gaza and across the region, has been in crisis since Israel accused a dozen of its staff of involvement in the October 7 Hamas attacks against Israel.

UNRWA fired some staff members as a result and the allegations are under investigation.

A UN-backed report this month said famine was imminent and likely to occur by May in northern Gaza.

James Elder, spokesman for the UN children's agency UNICEF in Gaza, described seeing "paper thin" children in a hospital in northern Gaza and incubators full of underweight babies from malnourished mothers.

"Tens of thousands of people crowd the streets," he told the same briefing, describing his latest visit to the north on Monday.

"They make that universal signal of hand to mouth desperately asking and seeking for food."

"Life-saving aid is being obstructed. Lives are being lost," he said.

"I saw children whose malnutrition state was so severe, skeletal," he said.

Children were dreaming of a slice of cucumber or begging for a tomato, Elder said.

Other aid agencies also deliver food parcels to northern Gaza, although UNRWA says it is the biggest provider.

Israel, which has vowed to destroy Hamas and is worried that the Palestinian militant group will divert aid, denies accusations by Egypt and UN aid agencies that it has delayed deliveries of humanitarian relief, saying the UN has failed to distribute aid within Gaza.

with DPA

Australian Associated Press