More than 100 workers with UNRWA, the United Nations agency for Palestinian refugees, have been killed since Oct. 7, the highest number ever seen in a single conflict, the agency said.

Those killed include parents, teachers, nurses and doctors, said Philippe Lazzarini, commissioner-general of UNRWA.

"Devastated. … UNRWA is mourning, Palestinians mourning, Israelis mourning," Lazzarini wrote, again calling for a humanitarian cease-fire.

During brief remarks in New Delhi Friday morning, U.S. Secretary of State Antony Blinken swiftly acknowledged the Biden administration’s “appreciation” of Israel’s commitment to four-hour pauses with three-hour notice in specific areas and corridors of Gaza “that will allow people to move more safely, freely to get out of harm's way and also to access assistance.”

“At the same time, much more needs to be done to protect civilians and to make sure that humanitarian assistance reaches them," he continued. "Far too many Palestinians have been killed. Far too many have suffered these past weeks, and we want to do everything possible to prevent harm to them, and to maximize the assistance that gets to them.”

The secretary said they have established basic principles to guide the effort for lasting peace and security in the region: no use of Gaza as a platform for launching attacks against Israel, no diminution in the territory of Gaza and a commitment to Palestinian-led governance.

Blinken reaffirmed that the administration had “long been committed” to a two-state solution, and the terror attacks of Oct. 7, he said, only redouble American commitment to the peace process.

“But now we've had the events of October 7 -- the almost, beyond the human imagination -- horror of October 7. And I think that only reinforces us in our conviction and our commitment to durable and lasting peace which again, we see through two states,” he said.

On humanitarian assistance, Blinken said that “more than plans, we have a concrete way forward,” including ensuring that there are adequate supplies of fuel for the trucks coming in and that hospitals and desalination plants “have what they need.”

“It's always a process and moving from an understanding, moving from an agreement to implementation is what we're working on right now,” he said.

Any plans for short-term pauses in the fighting in Gaza must be carried out in coordination with the United Nations, said Stéphane Dujarric, spokesperson for the U.N. secretary-general.

The U.N.'s comments come after the White House said Israel agreed to daily four-hour pauses in northern Gaza to allow civilians to escape.

"How any such halt in the fighting, and how it would work for humanitarian purposes, will need to be coordinated with the United Nations, especially on the issue of timings and location," Dujarric said. "And obviously in order for this to be done safely for humanitarian purposes, it would have to be agreed with all parties to the conflict to be truly effective."

Another 65 aid trucks entered Gaza through the Rafah border crossing on Thursday, a border crossing official said.

A total of 821 aid trucks have now crossed into Gaza as the humanitarian crisis worsens.

Dr. Ahmed Mokhallalati, the chief plastic surgeon at Al Shifa hospital in Gaza, told ABC News that he is unwilling to leave his scores of burn patients and stayed behind with the some 2,000 people left in the hospital complex and about 500 patients.

Mokhallalati said the hospital is virtually cut off because no one can get in -- they only received two or three patients on Saturday.

But despite having hundreds of burn patients, Mokhallalati doesn’t have much to do because they have only enough power for a single outlet to work. They use it in a clinic which has become the only operating room, because the real ORs require more power.

Mokhallalati said only about 15-20% of the hospital staff remain.

He also said there are some 40 infants in the neonatal units and 60 or so patients on ventilators, who he and the hospital administrators say will die once the generator fuel runs out.

The Israeli military’s civil coordinator said in a video statement Saturday that the eastern exit to the hospital is open, and that people are free to leave. But the images the Israeli military released from inside Gaza show that much of Gaza City and it’s outlying neighborhoods are flattened.

-ABC News' Matt Gutman and Sohel Uddin