Israeli forces killed and wounded dozens of Palestinians on Sunday in the northern Gaza Strip, after crowds gathered near a crossing from Israel to try to seize aid from United Nations trucks entering the enclave, according to the Gaza health ministry and health workers.

The episode was the latest in a string of deadly shootings as hunger and desperation have gripped Palestinians in Gaza during Israel’s nearly two-year campaign against Hamas.

The latest attack took place near the Zikim crossing between the Gaza Strip and Israel. More than 60 people were killed while seeking aid in northern Gaza on Sunday, according to the health ministry and Mohammad Abu Salmiya, the director of Al-Shifa Hospital in Gaza City.

A field hospital operated by the Palestine Red Crescent Society in northern Gaza was flooded with gunshot victims from the episode near Zikim. The hospital received two of the dead and more than 100 wounded, said Nebal Farsakh, a spokeswoman for the Red Crescent.

Israeli soldiers fired “warning shots” after thousands of Gazans gathered in the area, the Israeli military said in a statement. They had opened fire to “remove an immediate threat posed to them,” it added, but did not specify the nature of the threat.

The Israeli military also said that the reported number of casualties did “not align” with its initial review, but it did not provide an alternative toll. The military was continuing to examine the episode, it said.

The United Nations’ World Food Program said in a statement that a convoy of 25 trucks carrying food for Palestinians was entering northern Gaza when it “encountered massive crowds of hungry civilians which came under gunfire.”

The agency said it was “working with authorities to gather more details about the incident.”

Chaos has dominated aid distribution in Gaza amid widespread hunger in the territory. Israeli soldiers have repeatedly opened fire near huge crowds of desperate Palestinians heading to sites run by American contractors for the Gaza Humanitarian Foundation, a private and controversial Israeli-backed group, according to witnesses and the Israeli military.

At least 32 people were killed on Saturday after Israeli soldiers began shooting near a Gaza Humanitarian Foundation site in southern Gaza, according to the Gaza health ministry. The episode on Sunday did not occur near one of the foundation’s sites.

Shadi al-Nazli, 27, said he went to the border area on Sunday morning after hearing a rumor that trucks carrying flour would be entering through the Zikim crossing. The zone is known to be dangerous, as Israeli soldiers sometimes open fire if Palestinians get too close to the border, he said.

Palestinians frequently rush to seize aid from trucks as soon as they begin emerging from the Israeli side, Mr. al-Nazli said. Israeli soldiers shoot in an effort to keep the Palestinians away, but the desperate crowds are frequently undeterred, he said.

On Sunday, he said that “there were massive crowds of people, most of whom had spent the night there.” After the trucks crossed, the situation quickly devolved into gunfire, he said.

After the deadly shooting on Sunday, the Israeli military warned Palestinians to leave the populated areas of northern Gaza and parts of Gaza City that have been subject to previous evacuation orders, describing them as “combat zones.”

That followed an Israeli military order to Palestinians earlier in the day to evacuate parts of the central Gaza city of Deir al-Balah, one of the few areas in the territory where Israel has not conducted major ground operations during its military campaign against Hamas.

Many Palestinians had sought refuge around Deir al-Balah after being displaced several times from other parts of the enclave, because it has remained largely intact during the devastating 21-month Israeli campaign. The order to leave further shrinks the areas where the roughly two million residents of Gaza can live in relative safety and caused panic among Palestinians afraid that Israel was set to expand its ground invasion.

It was not clear if the evacuation notice portended an imminent expansion of Israel’s military incursion or was meant as a pressure tactic to wrest concessions from Hamas in the sluggish negotiations for a cease-fire.

More than 57,000 Palestinians, including thousands of children, have been killed during the war, according to the Gaza health ministry, which does not distinguish between combatants and civilians. The war was ignited by a Hamas-led attack on Israel on Oct. 7, 2023, in which some 1,200 people were killed and around 250 others taken hostage.

Many in Deir Al-Balah have been trying to find alternative accommodation, said Abdelhalim Awad, a local bakery owner.

“These are already areas packed with tent encampments,” Mr. Awad said. “People are wondering where else they can even go.”

Mr. Awad’s home is just north of where the Israeli military has ordered people to leave, and his bakery is in the evacuation zone. He said he feared the area where he lives may be next.

“This might be part of the negotiations — or the army might invade tomorrow,” he said. “There’s a lot of fear. We don’t know what will happen.”

Israeli ground forces have largely refrained from operating in a patch of central Gaza, including Deir al-Balah. The military has been worried that doing so could endanger the remaining hostages who were taken in 2023 and are believed to be held there, according to Israeli analysts.

The Hostages and Missing Families Forum, an Israeli organization that advocates for the hostages and their families, expressed alarm over the military’s announcement.

“Can anyone promise us that this decision will not come at the cost of losing our loved ones?” the group said in a statement, adding, “For the hostages, this is not a ‘card’ in negotiations, but a tangible and immediate danger to their fate.”

About 50 captives remain in Gaza, of whom about 20 are believed to be alive, according to the Israeli government. Hamas officials have said that their captors are under orders to kill the hostages should Israeli troops close in on them.

Myra Noveck and Gabby Sobelman contributed reporting.