Fighting is ongoing between Israeli forces and Hamas militants in southern Israel. Meanwhile, Israel and Hezbollah are openly exchanging fire at the northern border.

The Israel Defense Forces said the area of the Gaza Division has been declared a closed military zone and reiterated that entry is strictly prohibited.

The Rafah border crossing between Egypt and the Gaza Strip remained closed for the second day in a row on Wednesday. The crossing was shut indefinitely on Tuesday after it was hit by Israeli warplanes on the Palestinian side three times on Monday and Tuesday.

The State Department expects that the number of confirmed dead Americans will rise on Wednesday, State Department spokesperson Matt Miller said on CNN.

"We continue to work through the list of unaccounted and find that, obviously, some of those we will locate or will report in, some of them we do find, unfortunately, they're deceased, and then others we are able to confirm are taken hostage,” Miller said. “It's a moving target all the time."

-ABC News' Shannon Crawford

A barrage of rockets has landed on the Israeli city of Ashkelon on Wednesday morning.

Ashkelon, with a population of over 100,000 people, has essentially been a ghost town since the start of the incursion from Hamas over the weekend.

There have been no immediate reports of injuries or deaths in the aftermath of the attack.

-ABC News’ Matt Gutman

The United Nations said Wednesday that there are now more than 263,000 people internally displaced in the Gaza Strip, as Israeli airstrikes destroy buildings and homes in response to Saturday’s attack by Hamas.

That figure includes at least 137,500 people who are currently sheltering in hospitals and schools in Hamas-ruled Gaza, according to the U.N.

-ABC News' Joe Simonetti

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