JERUSALEM — A United Nations school sheltering displaced people in the southern Gaza Strip was hit Sunday by what a U.N. official said appeared to be an Israeli airstrike that killed 10 people as Israel signaled a possible scaling back in the ongoing war.

The military “is continuing to operate with full strength in order to complete the goals of the operation: The restoration of quiet and the restoration of security for a lengthy period for the citizens of Israel while inflicting significant damage on the terrorist infrastructures,” Netanyahu said in televised remarks from the Defense Ministry in Tel Aviv late Saturday.

The offensive, which Israel says was meant to curb rocket fire and destroy cross-border tunnels, has been the deadliest in Gaza since Israel withdrew settlers and soldiers from the territory in 2005. The Gaza Health Ministry says more than 1,700 Palestinians have died, including 400 children. Israel has lost three civilians and 64 soldiers, including a serviceman Netanyahu said was captured Friday.

The soldier, Lieutenant Hadar Goldin, was a relative of Defense Minister Moshe Ya’alon, Army Radio reported, after the military censor’s office allowed that detail to be published. The military declared him dead yesterday.

The United Nations warned of a “rapidly unfolding” health disaster and appealed for an end to almost four weeks of violence. A military spokesman, speaking anonymously today in line with regulations, had no further details on the revised troop deployment.

Ya’alon said at a briefing late last night that the tunnel operation — the stated objective of the ground operation Israel began July 17 after nine days of air strikes — is nearing completion.

Israel says Hamas and other militant groups encourage civilian casualties by locating weapons, command centers and other facilities in or near homes, mosques, schools and hospitals. The U.S. and European Union consider Hamas a terrorist organization.

Shlomo Brom, a retired general and senior fellow at the Institute for National Security Studies in Tel Aviv, said Netanyahu’s remarks suggest Israel may be weighing a unilateral pullout after multiple truce efforts collapsed.

“Instead of trying to reach an agreement with Hamas, which seems impossible, the government is going to withdraw most of its forces while staying very close in case they have to go in again,” Brom said. Israel and Hamas have accused each other of violating truce efforts, with the U.S. and U.N. blaming Hamas for the resumption of violence after the latest cease-fire they sponsored broke down Friday.

Hamas said a unilateral Israeli withdrawal wouldn’t necessarily mean it would stop fighting. “Actions in the field will determine our response,” the organization’s spokesman Sami Abu Zuhri said in an e-mailed statement.

Netanyahu, in his televised remarks, said the military operation “will take as much time as necessary, and will exert as much force as needed” to restore quiet to Israel. “We will deploy in the places most convenient to us,” he added.

Palestinian rights group Al-Mizan said more than 10,000 homes have been rendered uninhabitable by the Israeli strikes. Schools, medical centers, mosques, parks, a power station and water and sewage facilities have also been hit. Netanyahu said Israel was enlisting the international community to link the rehabilitation and development of Gaza to its demilitarization.

Previous cease-fires haven’t addressed the underlying issues of the proliferation of arms in the territory or Hamas’s demand to end a blockade that Israel initiated in 2006, citing security concerns, and Egypt joined.

In Cairo yesterday, Egypt’s President Abdel-Fattah el-Sisi said his country’s July 14 truce initiative, which Israel accepted and Hamas rejected, is still on the table.

While Hamas sent a delegation to talks in Cairo, according to Egypt’s state-run Ahram Gate website, Israel won’t because it doesn’t believe the group can be trusted to honor a cease-fire, Israel’s deputy defense minister, Tzahi Hanegbi, said in an interview with Channel 2 television. He said the renewed shelling of targets in Gaza will ensure that Hamas “won’t dare fire on us for years.”

The number of overnight Israeli strikes on Gaza dropped in comparison with similar eight-hour periods during the campaign, to 13, a military spokeswoman said, without offering comparative figures. Throughout the entire day yesterday, the military hit 153 targets, she said. Al-Qedra said an air assault on a house in Rafah killed 10 people, and that rescue workers were pulling dead and wounded from the rubble.

The United Nations sounded an alarm of an impending health catastrophe because of the conflict’s effect on medical facilities. The U.N. said in a statement that “at least half of all public health primary-care clinics are closed” and that “the hospitals and clinics that are still functioning are overwhelmed.’

Additionally, an estimated 460,000 people have been displaced and are living in overcrowded conditions in schools, with relatives or in makeshift shelters, according to the statement. This, coupled with inadequate water and sanitation, poses ‘‘serious risks of outbreak of water-borne and communicable diseases,’’ the U.N. said.

‘‘We are now looking at a health and humanitarian disaster,’’ James Rawley, the U.N. humanitarian coordinator in the area, said in the release. ‘‘The fighting must stop immediately,’’ he said.

Since the fighting in Gaza began, militants have fired more than 3,000 rockets at Israeli towns and cities and the Israeli air force has hit more than 4,600 targets in the seaside strip, according to the army. Israel says it has uncovered more than 30 infiltration tunnels.