Israeli strikes killed dozens of Palestinians in northern Gaza overnight, Palestinian health officials said on Wednesday, as Israel threatened to ramp up its military campaign in the enclave despite mounting international pressure.

The bodies of more than 50 people killed overnight had arrived at the Indonesian Hospital by noon on Wednesday, according to Marwan Sultan, director of the medical facility in the town of Beit Lahia. He said children were among the dead and that dozens more people had been injured.

Gaza’s health ministry also said that about 70 people had been killed on Wednesday, without specifying where.Gaza health officials do not distinguish between combatants and civilians when reporting death tolls.

Israel has been threatening a massive escalation across the Gaza Strip in an attempt to force Hamas to surrender and release the remaining hostages it has held for more than 18 months. The plan, as described by Israeli leaders, would displace many Gazans who, in some cases, have been forced from their homes or temporary shelters several times since the start of the war.

On Wednesday, the Israeli military said in a statement that its forces had struck Hamas and Islamic Jihad militants in northern Gaza, adding that it had sought to mitigate harm to civilians. An Israeli military spokesman warned Gazans in parts of the enclave’s north to flee in the face of an impending attack after rockets were fired at Israeli territory.

Odai Daama, a 23-year-old from Jabaliya — within the evacuation zone — said he had not seen the Israeli announcement because he did not have an internet connection. Around midnight, the strikes began, “hitting houses around us,” he said.

Later in the afternoon, the Israeli military ordered Palestinians to flee parts of Gaza City, including Al Shifa Hospital, warning of impending Israeli attacks. Israeli troops have raided the medical center at least twice during the war, with one assault leaving much of the complex in ruins.

Montaser Bahja, a teacher sheltering in an apartment just south of the evacuation zone, breathed a sigh of relief when he saw that his neighborhood might be spared — at least for now. Like many Gazans, he has been displaced multiple times during the war. His home in the northern city of Jabaliya, he said, is a heap of rubble.

“We can’t flee again. We just can’t. We’ve fled from house to house and now we’re here. It’s enough,” said Mr. Bahja. “We can only hope that our neighborhood stays safe.”

The Trump administration has been seeking to broker an end to the 18-month war, which Palestinian health officials say has killed more than 50,000 people and brought the enclave to the brink of starvation.

After Israel ended a two-month cease-fire with Hamas in March, Israeli forces resumed bombarding the Gaza Strip. Ground forces have also advanced deeper into the enclave, recapturing areas they had withdrawn from during the cease-fire.

Prime Minister Benjamin Netanyahu of Israel has more recently threatened an “intensive” escalation in Gaza unless Hamas lays down its weapons and turns over the hostages it still holds. The Israeli military has called up thousands of additional soldiers to bolster the war effort, and the government has vowed to seize additional territory there until Hamas complies.

The leaders of Hamas have refused to disarm and have said that they will not free the remaining hostages unless Israel ends the war and withdraws from the Gaza Strip.

On Tuesday night, Israeli fighter jets bombarded the southern Gaza city of Khan Younis in an effort to kill Muhammad Sinwar, one of the group’s top remaining military commanders. The Israeli military said it had targeted a Hamas complex underneath the European Hospital near Khan Younis.

Neither Israel nor Hamas have publicly commented on whether Mr. Sinwar was killed in the bombardment.

Israeli officials said they hoped eliminating Mr. Sinwar, one of Hamas’s most intransigent negotiators, would make the group more flexible on the demands for a truce. But Israel has assassinated numerous Hamas leaders since the beginning of the war, without compelling the group to accept its terms.

Mr. Sinwar’s older brother, Yahya Sinwar, led Hamas in Gaza and was one of the main planners of the Oct. 7, 2023, attack on southern Israel that ignited the war. After Yahya Sinwar was killed by Israeli forces last year, Muhammad Sinwar assumed a more prominent role inside the group.