"Gaza has been decimated" and life there is a "living hell," Philippe Lazzarini, commissioner-general of the United Nations Relief and Works Agency for Palestine Refugees in the Near East, said in an address to other U.N. officials on Monday.

He said the breakdown of civil order and "catastrophic levels of hunger" have caused looting and smuggling that are hindering the delivery of aid.

"Children are dying of malnutrition and dehydration, while food and clean water wait in trucks," he said.

Lazzarini also provided an update on the allegations that UNRWA staff members were involved in Hamas’ Oct. 7 terror attack on Israel.

He said out of 19 cases assigned to be investigated: one has been closed and the staffer was reinstated; four were suspended due to insufficient evidence; and 14 investigations are ongoing.

-ABC News’ Guy Davies

Eight people were killed Sunday in an Israeli airstrike on the UNRWA headquarters in Gaza City, according to the Hamas-run Gaza Ministry of Health.

The IDF said they were targeting Hamas infrastructure and took measures to reduce risk to civilians.

Witnesses told Reuters that the site was used to distribute coupons for aid and distribute water. Video shows a destroyed building and people moving bodies away from the rubble.

-ABC News' Victoria Beaule, Jordana Miller and Sami Zyara

Israeli Prime Minister Benjamin Netanyahu released a statement Sunday claiming there was a "dramatic decrease" in munitions from the United States starting some four months ago, and said he decided to talk about it publicly because of lack of change behind closed doors.

"Since the start of the war, the U.S. has given us support in spirit and in materiel -- defensive and offensive means. But four months ago, there was a dramatic decrease in the munitions coming to Israel from the U.S.," Netanyahu said in the statement. "For long weeks, we turned to our American friends and requested that the shipments be expedited. We did this time and again. We did so at the highest levels, and at all levels, and I want to emphasize -- we did so behind closed doors.

"We received all sorts of explanations, but one thing we did not receive; the basic situation did not change. Certain items arrived sporadically but the munitions at large remained behind," Netanyahu continued.

"After months in which there was no change in this situation, I decided to give this public expression," he said. "We did so out of years of experience and the knowledge that this step was vital to opening the bottleneck."

"In light of what I have heard over the past 24 hours, I hope and believe that this issue will be resolved in the near future," Netanyahu said, in part.

Last week, Netanyahu publicly claimed the Biden administration is broadly withholding military support for Israel amid its ongoing war with Hamas. Biden administration officials flatly denied the allegations.

Netanyahu, referring to a recent meeting with Secretary of State Antony Blinken in Israel, had said he told Blinken, "It's inconceivable that in the past few months, the administration has been withholding weapons and ammunitions to Israel."

Blinken had later declined to relate exactly what was said in private diplomatic conversations and did not deny that he had assured Netanyahu the U.S. was working to remove bottlenecks inhibiting the supply of American arms and ammunition to Israel.

-ABC News' Jordana Miller and Shannon K. Crawford

Strikes in multiple neighborhoods across northern Gaza today have killed 42 people according to Gaza's Civil Defense. Videos from the immediate aftermath of the strike show an entire building leveled, children covered in dust.

A bombing of Al-Shati camp killed 24 people, a bombing in Al-Tufaah killed 18 people -- the number of casualties is likely to increase -- and a bombing in Al-Zaytoun killed 7 people, according to Civil Defense.

Fifty others were injured in the attacks, according to the Hamas media office.

Several others are still trapped under the rubble.

The Israel Defense Forces told ABC News they struck two Hamas military infrastructure sites in Gaza City.