At least 67 Palestinians were killed by Israeli fire as they waited for United Nations aid trucks in northern Gaza, the Gaza health ministry said, as Israel issued new evacuation orders for areas packed with displaced people.
The ministry said dozens of people were also wounded in the attack in northern Gaza on Monday AEST.
It was one of the highest reported death tolls among reported recent cases in which aid seekers have been killed by Israeli gunfire, including 36 on the weekend.
Another six people were killed near another aid site in the south, it said.
Israel's military said its troops had fired warning shots towards a crowd of thousands of people in northern Gaza to remove what it said was "an immediate threat".
The UN World Food Programme (WFP) said that shortly after entering Gaza, a WFP convoy of 25 trucks carrying food aid encountered "massive crowds of hungry civilians" who then came under gunfire.
"WFP reiterates that any violence involving civilians seeking humanitarian aid is completely unacceptable," it said in a statement.
In total, health authorities said 90 people had been killed by Israeli gunfire and airstrikes across the enclave on the weekend.
Israel expands displacement orders
After Israel's military dropped leaflets urging people to evacuate from neighbourhoods in central Gaza's Deir al-Balah, residents said Israeli planes struck three houses in the area.
Dozens of families started leaving their homes, carrying some of their belongings.
Hundreds of thousands of displaced Gazans have been sheltering in the Deir al-Balah area.
Israel's military said it had not entered the districts subject to the evacuation order during the conflict and that it was continuing "to operate with great force to destroy the enemy's capabilities and terrorist infrastructure in the area".
Israeli sources have said the reason the army has so far stayed out is that they suspect Hamas might be holding hostages there.
Israeli airstrikes continue across Gaza as residents struggle to find food and water. Source: AP / Abdel Kareem Hana
Hostage families demanded an explanation from the army.
"Can anyone [promise] to us that this decision will not come at the cost of losing our loved ones?" the families said in a statement.
Accelerating mass starvation
Much of Gaza has been reduced to a wasteland during more than 21 months of Israeli bombardment, and there are fears of accelerating starvation.
Palestinian health officials said hundreds of people could soon die as hospitals were inundated with patients suffering from dizziness and exhaustion due to the scarcity of food and a collapse in aid deliveries.
"We warn that hundreds of people whose bodies have wasted away are at risk of imminent death due to hunger," the health ministry said.
The UN also said civilians were starving and needed an urgent influx of aid.
Pope Leo called for an end to the "barbarity of war" as he spoke of his profound pain over an Israeli strike on the sole Catholic church in Gaza that killed three people last week
Palestinians in Gaza said it was becoming impossible to find essential food such as flour.
The health ministry said at least 71 children had died of malnutrition during the war, and 60,000 others were suffering from symptoms of malnutrition.
It said 18 people have died of hunger in the past 24 hours.
Food prices have increased well beyond what most of the population of over two million can afford.
Several people who spoke to Reuters news agency via chat apps said they had either one meal or no meal in the past 24 hours.
"As a father, I wake up in the early morning to look for food, for even a loaf of bread for my five children, but all in vain," said Ziad, a nurse.
Others reported feeling dizzy while walking in the streets, and that many fainted as they did so.
Fathers leave tents to avoid questions from their children about what to eat.
UNRWA, the UN refugee agency dedicated to Palestinians, demanded Israel allow more aid trucks into Gaza, saying it had enough food for the entire population for over three months which was not allowed in.
