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.

At least three premature babies have died at the Al-Shifa Hospital in the Gaza Strip when a missile struck nearby and shut down the medical facility's backup generator, according to a doctor working at the hospital.

Dr. Ahmed Mokhallalti, the chief plastic surgeon at the hospital, told ABC News that the babies died when the power to their incubators was cut off Friday night into Saturday morning.

Mokhallalti said all of the hospital's ventilators were back up and running Sunday, but he expressed fear that more people would die at the hospital due to the relentless bombing.

Hospital officials said two patients in the hospital's intensive care unit also died on Sunday due to complications caused by the shelling.

The international humanitarian group Doctors Without Borders has made repeated calls for the shelling of hospitals in Gaza to cease.

"We are nearly sure that we are alone now. No one hears us," Dr. Mohammed Obeid of Doctors Without Borders said in a video statement from the Al-Shifa Hospital on Saturday.

Obeid said there are about 600 patients at the hospital who need medical care and need to be evacuated.

"The problem is [we need] to be sure we can evacuate the neonatal patients because we have 37 to 40 premature babies," Obeid said. "We have about 17 other patients in the ICU, and we have 600 postoperative patients who need medical care. So the situation is very bad. We need help."

-ABC News' Zoe Magee, Matt Gutman and Sami Zayara