Israel orders evacuations in Gaza City, as U.N. suspends food deliveries to the north because of looting.

Israel’s military ordered two neighborhoods of Gaza City to evacuate on Tuesday amid signs of hunger and mounting desperation in the northern part of the enclave at a time when the focus of Israel’s offensive has shifted south.

The evacuations came as the World Food Program halted deliveries in the north on Tuesday, describing scenes of chaos as its teams faced looting, hungry crowds and gunfire in recent days.

The fiercest fighting and most intense bombing has in recent weeks shifted south to areas around Khan Younis and Rafah. But the evacuation order from Israel’s military on Tuesday for the Zaytoun and Turkoman neighborhoods of Gaza City raised the possibility of further military moves in the north.

Northern Gaza has been decimated by four months of bombardment, and continued fighting there between Israeli forces and Hamas fighters has severely hindered deliveries of aid to the estimated 300,000 people still in the area, who the United Nations has warned face starvation.

The W.F.P. had suspended its deliveries for the past three weeks because of safety concerns, and on Sunday the agency tried to restart them, but “crowds of hungry people” surrounded the initial convoy as it was going to Gaza City, and aid workers were forced to fend off people trying to climb onto the trucks, the organization said in a statement.

Another convoy on Monday “faced complete chaos and violence due to the collapse of civil order,” the statement added, saying that several trucks were looted and a driver was beaten.

The W.F.P. said it did not take the decision to suspend deliveries in Gaza’s north lightly, adding it said means “more people risk dying of hunger.”

“W.F.P. is deeply committed to urgently reaching desperate people across Gaza but the safety and security to deliver critical food aid — and for the people receiving it — must be ensured,” the statement said.

It cited the “unprecedented levels of desperation” witnessed by its teams as evidence of Gaza’s “precipitous slide into hunger” and pointed to a U.N. report published on Monday that said acute malnutrition has surged in the northern part of the enclave.

Northern Gaza was the initial target of Israel’s military offensive. As Israeli forces pushed deeper into Gaza, the military urged civilians to move south for their own safety.

Hundreds of thousands heeded the calls, and more than half of Gaza’s population is now crowded into Rafah, living in temporary lodgings and tents. But widespread shortages of food and water, coupled with concerns that nowhere in Gaza was truly safe, prompted some of the displaced to return to the north.

The new evacuation notice given by Israel’s military on Tuesday told people in the two Gaza City neighborhoods to move to a area around the seaside village of Al-Mawasi, west of Khan Younis in the southern part of the enclave. The notice was posted in Arabic on social media, but communication networks have been severely disrupted in Gaza so it was unclear how many people saw it.

Ameera Harouda and Rawan Sheikh Ahmad contributed reporting.