The Israeli military pressed deeper into northern Gaza by ground on Friday after issuing a series of evacuation orders calling on Palestinians to flee, part of its escalating offensive against Hamas in the war-battered Gaza Strip.
The expansion of ground operations came after the Palestinian health authorities said on Thursday that dozens of people, including children, were killed in Israeli strikes on a school turned shelter in the Tuffah neighborhood of Gaza City. On Friday, the Israeli military said the strikes were targeting well-known militants in a Hamas command and control center, without naming them.
The evacuation orders have brought renewed hardship to Palestinians who had already endured displacement from their homes and miserable conditions during the first 15 months of the war. A shaky two-month-old cease-fire between Israel and Hamas collapsed in mid-March after the two sides failed to reach an agreement to extend it, ending a brief respite for Palestinians in Gaza.
The Israeli military has since embarked on a major bombing campaign and seized territory in Gaza in a tactic that Israeli officials have said was intended to compel Hamas to release more hostages.
Avichay Adraee, the military’s Arabic-language spokesman, said in a post late Thursday on social media that he was providing a “final” warning before a new attack, urging people to relocate southward. Mr. Adraee suggested that militant groups were operating among civilians.
While many people have complied with such evacuation orders from the military during the most recent Israeli campaign, others have chosen to stay in their homes or shelters, saying they could not bear being displaced or that they have nowhere else to go.
On Friday, the military said its troops began operating in the neighborhood of Shajaiye in eastern Gaza City in order “to expand the security zone,” referring to what it has characterized as a buffer zone next to Israel’s border with Gaza.
The military said Israeli soldiers had killed militants and dismantled weapons infrastructure, including a Hamas command and control center, without offering specifics. During the first 15 months of war, much of Shajaiye was transformed into a wasteland as the Israeli military fought Hamas, with buildings demolished, roads ripped up and utilities infrastructure ruined.
Ahead of the truce in January, Israeli forces had stormed Gazan cities before withdrawing, allowing Palestinian militants to regroup in the rubble.
Palestinian health authorities — who do not distinguish between civilians and combatants — said the bodies of 27 people killed in the Tuffah strike had arrived at the hospital.
Multiple videos verified by The New York Times show an explosion and its chaotic aftermath at the Dar al-Arqam school, where civilians were sheltering. The strikes were followed by a chaotic scene at Al Ahli Arab Hospital in Gaza City, where dust-covered and bloodied children were rushed from vehicles.
Khamis Elessi, a volunteer doctor at the hospital, said successive waves of wounded people arrived in the emergency room, overwhelming medical staff.
“It was a terrifying scene,” he said in phone interview. “People were thrown on the ground.”
Dr. Elessi, 56, said he was stunned by the number of wounded children. “I was brought to tears,” he said. “One boy kept asking me: Why did they hit me?”
One of those killed was the grandson of Khalil al-Hayya, Hamas’s top negotiator based in Qatar, the Hamas-run Al Aqsa TV channel reported.
Israel has previously targeted schools being used as shelters, contending that Hamas militants were operating command centers in them. Hamas has denied such claims in the past. The United Nations has said that Israeli strikes on schools probably violated the law by causing disproportionate harm to noncombatants.
More than 1,000 people in Gaza have been killed since the collapse of the cease-fire on March 18 and more than 50,000 people have been killed since the start of the war, according to the Gaza health ministry. The bodies of 86 people killed by Israel arrived at hospitals across Gaza on Thursday, according to the health ministry.
The war started after Hamas-led forces attacked Israel, killing roughly 1,200 people.
Nader Ibrahim and Ameera Harouda contributed reporting.
