The new controversial US- and Israeli-backed Gaza Humanitarian Foundation (GHF) began operations at an aid distribution centre in southern Gaza on Tuesday.
Chaotic scenes ensued as thousands of Palestinians rushed into the centre in Rafah, AFP journalists and local authorities reported.
"We have seen yesterday the shocking images of hungry people pushing against fences, desperate for food. It was chaotic, undignified and unsafe," the head of the UN agency for Palestinian refugees (UNRWA) Philippe Lazzarini said in Tokyo.
The incident came days after the partial easing of a total aid blockade on the territory that Israel imposed on March 2, leading to severe shortages of food and medicine.
Gun shots
The Palestinian Health Ministry in Gaza said at least one person was killed and 48 others wounded when Israeli forces opened fire on crowds overrunning Gaza aid site.
Earlier, the United Nations human rights office said on Wednesday that scores of people were injured while trying to receive food aid on Tuesday at distribution sites in Gaza operated by the GHF.
"47 people were injured due to gun shots," Ajith Sunghay, Head of the United Nations Office of the High Commissioner for Human Rights in the Occupied Palestinian Territory told reporters in Geneva, citing information from partners on the ground.
The gunfire was from the "Israel Defense Force", he said.
The UN Human rights office could not give a specific location of where people were injured.
'Disastrous failure'
The US, meanwhile, claimed distributing hundreds of thousands of meal boxes to Palestinians "who desperately need it".
US State Department spokesperson Tammy Bruce said on Tuesday that the joint US-Israeli aid group delivered 462,000 meals through 8,000 food boxes.
Bruce declined to address reports of attacks by the Israeli army on Palestinians rushing to the aid distribution facility in the southern city of Rafah, focusing instead on the foundation's aid delivery achievements.
The Palestinian Government Media Office in Gaza, issuing a statement the same day, said, "The Israeli occupation's plan for aid distribution in the so-called buffer zone has failed disastrously."
Risking humanitarian priorities
The United Nations Office for the Coordination of Humanitarian Affairs (OCHA) warned that the aid distribution by the GHF risk distracting from the urgent humanitarian priorities in Gaza, such as sustained access, safe conditions and expedited approval of emergency supplies.
The foundation, set up in February, has been highly criticised by the United Nations, whose officials have said its aid distribution plans would only foment forced relocation of Palestinians and more violence.
A global hunger monitor has warned that starvation looms over half a million people, a quarter of the population in Gaza.
Israel has kept Gaza crossings closed to food, medical and humanitarian aid since March 2, deepening an already severe humanitarian crisis in the enclave, affecting Gaza's 2.4 million residents.
