National Security Council spokesman John Kirby, explaining what Secretary of State Antony Blinken meant earlier when he said there would be a "transitional period" in Gaza, said a post-war Gaza will go through a "period of time" where Israeli forces remain on the ground.

"I think all of us can foresee a period of time after the conflict is over where Israeli forces will likely still be in Gaza and will have some initial security responsibilities. But for how long and where and to what size and scale and scope, I think it’s too soon to know that," he said on CNN.

Israeli Prime Minister Benjamin Netanyahu told ABC News "World News Tonight" anchor David Muir that Israel would have the "overall security responsibility" of Gaza for an "indefinite period."

-ABC News' Justin Ryan Gomez

Senate Majority Leader Chuck Schumer said Tuesday that he spoke to Israeli Prime Minister Benjamin Netanyahu and other Israeli leaders on Monday and reiterated to them that the "U.S. has Israel's back in this dark hour."

Schumer said he told Netanyahu that they must work to protect Palestinian lives, and said he urged Israeli leaders to stop the settler violence against Palestinian civilians in the West Bank.

Israel has "a responsibility to protect innocent Palestinian civilian life. We know this is not easy, but it must be done," Schumer said. "We must likewise work together to send critical humanitarian aid to innocent civilians in Gaza who have nothing to do with Hamas."

"I also strongly urge the Israeli government to quickly clamp down on settler violence against and displacement of Palestinian civilians in the West Bank. Violence and displacement against these Palestinian civilians is not just wrong -- it risks spreading the current crisis beyond Gaza at a time when Israel and America are working hard to deter other actors from taking advantage of the situation," Schumer said.

-ABC News' Mariam Khan

The United Nations Relief and Works Agency for Palestine Refugees in the Near East said 92 of its employees have now been killed in Gaza, the highest number ever seen in a single conflict.

"We are never going to be the same without them," UNRWA Commissioner-General Philippe Lazzarini said. "Once again I call for a cease-fire for the sake of humanity."

A civilian evacuation corridor from northern Gaza to southern Gaza opened again on Wednesday.

"Due to the substantial response," the corridor was open for an extra hour, running from 10 a.m. to 3 p.m. instead of ending at 2 p.m., "allowing many more Gazans to move south for their safety," the Israel Defense Forces said.

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