Philippe Lazzarini said an increase of skin diseases was also impacting the people of Gaza which he said was unsurprising considering the unsanitary conditions there.
He described the situation for most as "desperate" as "people are lacking everything."
Lazzarini said he was in "full admiration" of the U.N. staff who have endured the same terrifying experiences as the people living in Gaza.
He reassured that "UNRWA will stay. UNRWA has stayed. And we will scale up our footprint, scale up our presence, scale up our activities."
Gaza has received only 10% of its required food supplies each day in shipments from Egypt, according to the U.N., and the water system shutdown has left most of the 2.5 million population drinking contaminated water.
Dehydration and malnutrition are growing, according to the U.N.’s World Food Program. On Friday, the United Nations was forced to stop deliveries of food and other necessities to Gaza and warned of the growing risk of widespread starvation after internet and telephone services collapsed in the besieged enclave because of lack of fuel.
The besieged territory awaits the rewards of a Washington-Qatar brokered cease-fire that is expected to see a hostage-prisoner exchange between Israel and Hamas. Egyptian state media said the four-day truce agreed between Israel and Hamas — the Palestinian militant group — will begin Thursday morning, the Associated Press reported Wednesday.
The war erupted in early October, when several thousand Hamas militants broke into southern Israel, killing at least 1,200 people — mostly civilians — and taking hostages.
Weeks of devastating Israel airstrikes in Gaza — followed by a ground invasion — have killed more than 11,000 Palestinians, according to the Health Ministry in the Hamas-run territory.
It does not differentiate between civilians and militants, though some two-thirds of the dead have been identified as women and minors.
The ministry said that as of November 11 it had lost the ability to count the dead because of the collapse of large parts of the health system, but says the number has risen sharply since then. Some 2,700 people are missing and believed buried under rubble.