Prime Minister Benjamin Netanyahu visited Israeli troops fighting in the Gaza Strip on Monday, vowing to stay the course of the war even with the death toll mounting. His trip came hours after Gazan health officials reported that a devastating overnight strike on a crowded neighborhood had killed dozens.

The trip was the Israeli leader’s second known visit to Gaza since the war began. Mr. Netanyahu has been facing increasing pressure from the United States to lower the intensity of the war, but he said on Monday that Israel would “deepen” the fighting in coming days.

The strike late Sunday in central Gaza underscored the risk to civilians as fighting intensifies. Gazans were mourning the victims in the neighborhood, Al Maghazi, where many who have fled fighting in other parts of the enclave have sought shelter.

Photos of the aftermath on Monday showed a gray concrete building gaping with dark holes where rooms used to be. At the foot of the building was a mound of debris, where men appeared to be digging for survivors, or bodies, without the aid of any heavy equipment.

The Gaza Health Ministry said 70 people had died in Sunday’s attacks on Al Maghazi. But the ongoing difficulty of reaching residents in Gaza, where electricity shortages and communications blackouts have frequently obscured the picture of the war’s fallout, meant the details were blurry.

As the Gazan death toll has soared and civilians have been pushed into smaller and smaller corners of the enclave, international calls for a cease-fire have grown. While Mr. Netanyahu’s government has said it is planning for a new phase of the fighting, the Israeli leader has repeatedly insisted that his military would keep up the war in Gaza until all of its goals were achieved.

“We’re not stopping, we are continuing to fight and are deepening the fighting in the coming days,” he said in a statement released by his Likud Party on Monday, adding that “this will be a long battle and it is not close to ending.”

Gazan Health Ministry officials blamed Israeli airstrikes for the deadly attack on the Al Maghazi neighborhood of central Gaza. Israel’s military said Monday it was reviewing the episode.

Israeli forces are pushing deeper into central Gaza while also continuing to battle Hamas fighters in the enclave’s north and south. Many places in central and southern Gaza are crowded with people who have fled their homes.

“These rockets, it’s like they’re made to destroy mountains, not people,” said Mohamed Abu Shaah, who had taken shelter at an acquaintance’s house in Al Maghazi with his wife and seven daughters. In Al Maghazi, he said, the influx of the newly displaced meant that 20 people were routinely crowding into a single room to sleep at night.

It was the fifth time his own family had packed up and rushed to a new place after fighting and airstrikes threatened the place they had taken shelter.

“We are doing everything we can just to run for our lives,” he said.

The rising death toll in Gaza, which health ministry officials have said stands at about 20,000 people prompted Pope Francis on Monday to focus his Christmas address in part on the plight of Palestinians, as well as on Israeli hostages held in Gaza.

He mentioned Bethlehem, the holy city in the Israeli-occupied West Bank where officials have largely canceled Christmas festivities in solidarity with Palestinians in Gaza, and pleaded for peace to “come in Israel and the Palestinian territories, where war is devastating the lives of those peoples.”

The pope also called for “an end to the military operations with their appalling harvest of innocent civilian victims,” and “for a solution to the desperate humanitarian situation by an opening to the provision of humanitarian aid.”

Gaza is controlled by Hamas, the armed group that led the Oct. 7 attacks on Israel that Israeli officials say killed about 1,200 people.

Mr. Abu Shaah said he had just returned from prayer late Sunday night and was about to put his daughters to sleep in the bed that nine of them shared when they heard a loud thud. Afraid they would find themselves under the rubble, they ran downstairs to a scene of devastation.

“We’ve seen a lot, but this is beyond anything we could have imagined,” he said. “Today my family and I are alive, but what about tomorrow?”

Before the war, about 33,000 Palestinians lived in Al Maghazi, an area covering only about a quarter of a square mile, according to the United Nations agency that aids Palestinians. Most families in the neighborhood were originally from villages in the center and south of what was Palestine before they fled or were forcibly displaced in the 1948 war that surrounded Israel’s establishment as a state.

The neighborhood has been hit multiple times before, according to U.N. reports.

Save the Children, an aid group, called the strike on Al Maghazi “another episode of the ongoing horror” in Gaza.

“Families and children are not targets and must be protected,” it said in a post on X, formerly known as Twitter. “We need an immediate and definitive cease-fire to end this misery.”

Jason Horowitz contributed reporting from Rome.