Shortly after crossing through the northern Zikim crossing into Gaza, a 25-truck convoy from the World Food Programme (WFP) encountered large crowds of civilians waiting to access food supplies, the UN agency said on social media platform X.
"As the convoy approached, the surrounding crowd came under fire from Israeli tanks, snipers and other gunfire."
The incident, on Sunday morning local time, resulted in the loss of "countless lives" with many more suffering critical injuries, the WFP said.
"These people were simply trying to access food to feed themselves and their families on the brink of starvation. This terrible incident underscores the increasingly dangerous conditions under which humanitarian operations are forced to be conducted in Gaza."
Local health authorities reported 67 Palestinians were killed, while Palestinian news agency WAFA reported 58 dead and at least 60 injured.
The Israeli military said warning shots had been fired amid "an imminent threat" and expressed doubts about the reported casualty figures.
The details of the incident are currently being investigated, the military said, but added an initial review indicated that the reported casualty figures do not match the information provided by the army.
The information could not be independently verified at first.
WAFA, citing medical sources, reported that 132 people had been killed in the Gaza Strip on Sunday, including 94 aid seekers.
The UN and aid organisations report catastrophic conditions in the Gaza Strip, whose almost two million residents are almost entirely dependent on aid to survive.
Gaza residents have been subjected to almost 22 months of fighting between Israel and Palestinian militant group Hamas.
According to UN figures, hundreds have died in the vicinity of aid distribution points and around aid convoys since the end of May.
WAFA put the death toll from Israeli military operations in the Gaza Strip since October 2023 at at least 58,895, with more than 140,980 injured. The agency cites Palestinian medical sources for its figures.
The Israeli army is expanding its operations in the city of Deir al-Balah in the centre of the Gaza Strip, according to a statement from an army spokesman, who called on residents to leave the area in a post in Arabic on X.
The Israeli military continues "to operate with intensity to eliminate terrorists and to dismantle terrorist infrastructure in the area and is expanding its activities into new areas," the army said in a statement.
"For your safety, immediately evacuate southward toward Al-Mawasi."
Al-Mawasi in the south-west of the embattled area was designated by Israel as a "humanitarian zone" earlier in the war.
However, the Israeli military has since also attacked there multiple times. The army said targets included facilities of Hamas.
The UN Office for the Coordination of Humanitarian Affairs warned the mass displacement order had dealt "yet another devastating blow" to the Gaza Strip.
Initial estimates indicated that between 50,000 and 80,000 people were in the area at the time the order was issued, including some 30,000 people sheltering in 57 displacement sites, the UN office said.
The newly designated area included several humanitarian warehouses, four primary health clinics, four medical points, and critical water infrastructure, it said.
"Any damage to this infrastructure will have life-threatening consequences."
12°C