As the humanitarian crisis in Gaza continues to worsen by the day, Jens Laerke, spokesperson for the United Nations humanitarian office, said, "If there is a hell on earth today, its name is northern Gaza."

"People who remain there, the corners of their existence are death, deprivation, despair, displacement, and literally, darkness," Laerke said. "The entire Gaza Strip has been plunged into darkness. … What do you tell your children in such a situation? It's almost unimaginable."

People are fleeing Gaza's Al-Shifa hospital, sources confirmed to ABC News, in the wake of a strike on the exterior area of the hospital's outpatient clinic. One surgeon told ABC News "everyone" has fled, calling it a "nightmare."

The hospital has been treating thousands of wounded people and housing as many as 80,000 displaced residents, according to The Associated Press.

The hospital's head of plastic surgery, Dr. Ahmed Mokhallalati, told ABC News he is among the roughly 15% to 20% of staff members still there on Friday.

Although many patients have evacuated, he said, "There is no hospital in Gaza that can accommodate this number of ICU patients -- around 100 ICU patients."

The Palestinian Red Crescent said occupation snipers fired on Gaza's Al-Quds Hospital, killing at least one and injuring at least 28.

Israel Defense Forces spokesman Richard Hecht said, "The IDF does not shoot at hospitals. If there are Hamas terrorists in the hospitals, the IDF will do what it needs to, but we are aware of the sensitivity. We tell Hamas to move the sick southward."

"Slowly we are closing in on them and taking every precaution not to harm the innocent," he said.

American diplomats abroad are giving stark warnings about the long-term ramifications of the war, telling their Washington counterparts in multiple diplomatic cables that their work and public opinion of the U.S. in the Arab world could be lost and denigrated for a generation, a State Department source told ABC News.

Diplomatic cables are how U.S. embassies around the world privately communicate with State Department leadership about what U.S. diplomats are seeing on the ground. While some are just regular updates, others contain candid assessments and analysis about what senior embassy staff are seeing on the ground and the potential impacts on U.S. foreign policy or the U.S. standing in the region.

Twelve kids with cancer or other blood disorders have been evacuated with their families from Gaza to Egypt or Jordan so they can continue their treatment, the World Health Organization said.

More kids with cancer are expected to be evacuated, the agency said.

"I am relieved that children in vital need of cancer care have been able to leave the insecurity and uncertainty in Gaza and continue receiving life-saving treatment," WHO Director-General Dr. Tedros Adhanom Ghebreyesus said in a statement. "This show of desperately needed humanitarian action should serve to motivate increased access to life-saving care to all people affected by this conflict, both inside Gaza where needs are greatest today, and beyond. I pray this initiative can inspire all parties to put health and peace first."

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