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 his first on-camera comments about Israel’s evacuation request for northern Gaza, Israeli Defense Minister Yoav Gallant urged Gaza residents to head south. He noted that Hamas will use them as "camouflage," “therefore we need to separate them."

"Those who want to save their life, please go south. We are going to destroy Hamas infrastructures, Hamas headquarters, Hamas military," he said.

Defense Secretary Lloyd Austin, who appeared at the press conference with Gallant, dodged ABC News' question about how Israel could end the Hamas terror threat without inevitably risking civilian lives. Austin called Israel's military "professional" and "disciplined."

Austin described how ISIS had also embedded themselves in civilian populations and how the anti-ISIS coalition "protected civilians and created corridors for humanitarian movement even in the midst of a pretty significant fight. So again, this is a professional force. It is well led, and I have every expectation that it will be disciplined."

Austin added, "I would tell you that in countering ISIS, I felt as if we were staring evil in the eye, it was truly evil. And what we've seen from Hamas, it takes that evil to another level."

-ABC News' Matt Seyler and Luis Martinez