Egypt, Israel and the United States have agreed to allow foreigners in Gaza to pass through the Rafah border crossing into Egypt, according to a senior State Department official.

“So we have been trying to facilitate access for [the Rafah Border Crossing] to be open from 12 to 5 today. The Egyptians, the Israelis and the Qataris have been working with us on that,” the official said.

They added: “That said, it’s not clear at all if Hamas was going to allow people to make it to Rafah.”

When asked about the number of U.S. citizens, the official said, “We are in touch with a number of the roughly 500-600 (Palestinian-Americans)…who have expressed interest in receiving information about leaving.”

-ABC News' Shannon Crawford

Early Saturday morning, Israel Defense Forces Lt Col. Jonathan Conricus went live on X to give an update on the 24-hour evacuation notice issued in Gaza on Friday.

Conricus stated, "The Palestinian citizens in Gaza are not our enemies," saying IDF doesn’t assess them as such, and if they did "the situation in Gaza would be different."

"We have seen a significant movement of Palestinian civilians toward the south, we have seen people listening to our warning, understanding that they are moving out of a dangerous area," said Conricus.

The IDF advertised their intentions in advance "not because it has any military logic" but because "we want civilians not to be affected by the war," said Conricus.

"They are not our enemy, we are not trying to kill or injure any civilians, we are fighting against Hamas."

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

Six days after a brutal attack by armed Hamas militants on Israeli civilians, Israel ordered an evacuation of more than 1 million Palestinians in northern Gaza ahead of what could be an unprecedented ground offensive there against Hamas.

The U.S. and other nations have repeatedly warned Israel to follow the "rules of war."

But what are they? And will they prevent civilians from being hurt?

Here's what to know about international humanitarian laws and how they might apply in the Israeli-Hamas conflict in Gaza.

-ABC News' Anne Flaherty

In remarks with Israeli Prime Minister Benjamin Netanyahu, Secretary of State Antony Blinken said at least 25 Americans had now been confirmed dead in Israel.

Netanyahu described some of the atrocities committed by Hamas.

"Hamas has shown itself to be an enemy of civilization: The massacring of young people in an outdoor music festival, the butchering of entire families, the murder of parents in front of their children and the murder of children in front of their parents. The burning of people alive, the beheadings," he said.

"Hamas should be treated exactly the way ISIS was treated," he said. "They shouldn't be spit out from the community of nations. No leader should meet them. No country should harbor them. And those that do should be sanctioned."

Blinken said he was speaking not only as an American diplomat, but as a Jew, a husband and a father of young children, saying it was impossible for him to look at photos of families killed "and not think of my own children."

"The same time that we've been shocked by the depravity of Hamas, we've also been inspired by the bravery of Israel citizens," he said. "The grandfather who drove over an hour to a kibbutz under siege, armed only with a pistol and rescued his kids and grandkids. The mother who died shielding her teenage son with her body, giving her life to save his -- giving him life for a second time."

Blinken remarked that some U.S. aid had already been delivered, and that more military aid was on his way. He said the administration would work with Congress to meet Israel’s additional needs and that bipartisan support for Israel was "overwhelming."

The secretary called on world leaders to condemn Hamas.

Blinken also reiterated that Israel "has the right -- indeed, the obligation -- to defend itself" but that it was "so important to take every possible precaution to avoid harming civilians."

-ABC News' Shannon Crawford