The Israel Defense Forces said its fighter jets have killed Iman Nofal, a senior Hamas member who was a former leader of Hamas' military intelligence.

Gaza hospitals are estimated to have less than 24 hours of fuel left, according to the United Nations Relief and Works Agency.

President Joe Biden departs for the Middle East on Tuesday for in-person meetings with Israeli and Arab leaders amid concerns of an expanded conflict in the Israel-Hamas war.

National Security Council spokesman John Kirby told "Good Morning America" that Biden's focus is on the hostage situation, to make sure humanitarian aid can flow to civilians in Gaza, and to get an update from Israeli counterparts on their plans and ground operations.

Asked about safety concerns, Kirby said "there’s always a concern" wherever the president goes, and those concerns would be "appropriately addressed through the necessary force protection and personnel protection measures. "

Asked if Biden's visit also includes urging Israel to avoid a full-scale ground invasion of Gaza, Kirby reiterated that the U.S. is not telling the Israeli military how to operate but that civilians should be protected.

Kirby added that it's "vital" that the administration gets supplemental funding from Congress for Israel and Ukraine.

-ABC News' Justin Gomez

The Egyptian Food Bank has nearly 3,000 tons of aid, including food, medicine and blankets, ready to cross into Gaza to help its trapped residents, its CEO said. But for now, the trucks are sitting still as the Gaza-Egypt border remains closed.

Mohsen Sarhan, the CEO of the Egyptian Food Bank, told ABC News he went to the border on Tuesday morning.

"You can see people dying, like, few miles away from you," he said. "Everyone in the world knows that these people have run out of water, and they have run out of medicine and have they have run out of food. And you have all that right in front of you. And you can't give it to the people. It's a human rights crisis. And it's very frustrating."

-ABC News' Matt Rivers

Human Rights Watch has accused Israel of using white phosphorus munitions in military operations in Gaza on Wednesday, saying it violated international humanitarian law by putting civilians at unnecessary risk.

In a report released Thursday, Human Rights Watch said it based its determination on a video it said it has verified, as well as two eyewitness accounts.

The Israel Defense Forces said in a statement to ABC News that claims they used white phosphorus in Gaza are "unequivocally false."

ABC News geolocated a video showing a jellyfish-shaped plume of white smoke over the port of Gaza. The video was posted on Wednesday by the official Palestinian news agency WAFA and matches images posted on social media and by other news outlets on the day.

Two experts -- Amael Kotlarski, the weapons team manager for the defense intelligence firm Janes, and Amnesty International weapons investigator Brian Castner -- told ABC News that images suggested munitions deployed over the port of Gaza on Wednesday appeared to contain white phosphorus.

"We have verified that Israeli artillery forces striking Gaza are equipped with M825 and M825A1155mm white phosphorus projectiles," Castner told ABC News, pointing to photographs by an Anadolu Agency photographer taken on Monday and showing Israeli troops handling shells labeled "M825A1."

Kotlarski said visual evidence alone was not sufficient to confirm that these specific shells were used in the Gaza port strikes.

There are "perfectly legal" military uses for white phosphorus munitions, Kotlarski said, including to create a smoke screen to conceal movements, to mark targets for artillery or air strikes, or to illuminate a battlefield. However, its use in urban areas is "problematic due to the higher risk of collateral damage," Kotlarski said, including the munitions' potential to cause severe burns.

White House Principal Deputy Press Secretary Olivia Dalton said Friday the U.S. had not independently verified allegations Israel used white phosphorous "so that is not something I would want to speculate about or weigh in on at this time."

-ABC News' Christopher Looft, Ben Gittleson and Jordana Miller