Nearly half a million people with no place to go have left Rafah in southern Gaza ahead of Israel’s long-anticipated offensive, but the Israeli military has continued striking all areas of the Gaza Strip.

Israeli warplanes targeted a building in the Nueseirat refugee camp in central Gaza, killing several people — including women and children — while survivors had to be dug out of the rubble.

In another strike nearby, the Israeli Defense Forces said it struck a “Hamas war room” at a U.N. school. Israel said it killed more than 10 fighters, although CBS News could not independently verify that claim.

The carnage comes as aid agencies say hundreds of thousands of Palestinians have fled Rafah since Israel began targeting areas there last week. One of those who fled is 81-year-old Mustafa al-Gazzar, now displaced and living in a temporary camp.

“I live in extreme fear,” he told CBS News.

All crossings out of Gaza are now blocked, leaving 20 American medics trapped inside. 

“It’s been very difficult, leaving my wife and my two kids and surrounding family. It was something that I had to do,” Dr. Mohammed Abdelfattah, from California, told CBS News. “I felt like the efforts back home were not going anywhere, they were falling on deaf ears.”

Abdelfattah was originally scheduled to leave Gaza on Monday, but now he’s stuck inside the strip’s European Hospital in Al-Fukhari, near Khan Yunis. He said the imminent operation in Gaza has led to fear among local residents.

“The locals have told me multiple times that there’s no safe place in Gaza. They’ve seen over the past six, seven months, hospitals have been targeted, mosques have been targeted, churches, bakeries,” he said. “Currently we are in a green zone, a ‘safe zone,’ but the population know there is no safe zone in Gaza.”

Abdelfattah said many of the patients in the ICU are young children with “severe burns and explosive injuries that will pretty much lead to a guaranteed death here, and that’s what I’ve seen because of the lack of resources, the lack of supplies.”

“This is all intentional,” he added. “This is not a natural disaster. This is an intentional disaster that’s being inflicted on these people with the backing of my government.”

President Biden has become increasingly critical of how Israeli Prime Minister Benjamin Netanyahu has carried out the war and Gaza, going so far as to pause shipments of some weapons to Israel because of concerns about the IDF’s plans in Rafah. But Abdelfattah told CBS News it’s not enough. 

“There’s American weapons being dropped on the people of Gaza every single hour, and our American government — President Biden —  has the power to stop all of this with just one phone call,” he said.

Abdelfattah said multiple people have told him, “The one thing that is giving us hope right now is the student protests that are occurring across the nation back home.”

Meanwhile, Israel on Tuesday celebrated 76 years since the nation’s founding. But amid the subdued commemorations, thousands of Israeli settlers marched toward Gaza, blocking aid from entering and demanding the right to build settlements inside the Palestinian territory.

Aid agencies are warning that over a million Palestinians now face catastrophic levels of hunger. A floating pier Mr. Biden ordered built to help ramp up the distribution of aid could become operational soon, allowing for more food and supplies to enter the territory.

Imtiaz Tyab

Imtiaz Tyab is a CBS News correspondent based in London.