UNRWA, the U.N. relief and works agency for Palestinian refugees, warns that the conflict is posing very real threats to international peace and security as well as the lives of nearly the entire population in Gaza.

In a letter sent Thursday to the president of the U.N. General Assembly, UNRWA Commissioner-General Philippe Lazzarini said his agency’s ability to continue delivering its mandate in Gaza “has now become very limited.”

“With constant bombardment, low and irregular flow of food and other humanitarian supplies into the Gaza Strip compared to the immense needs of displaced people in our overcrowded shelters and outside, UNRWA’s ability to assist and protect people is reducing fast,” he said.

WHO spokesman Lindmeier said that WHO convoys carrying food, water and medical supplies have been stopped from entering Gaza more than once and that Friday’s operation to bring medical supplies to the north and evacuate 12 patients to the south for medical treatment had been suspended.

“The situation in Gaza is beyond belief,” he said. “The health system is on its knees,” and the south could experience the same fate as the north.

“Gaza cannot afford to lose a single hospital or any single hospital bed. … Patients are bleeding on the floor. Trauma yards resemble battle fields,” said Lindmeier.

“This must end. This callousness must end,” he said. “We need a cease-fire, and we need it now. VOA News