The majority of those killed were in the vicinity of Gaza Humanitarian Foundation sites, while the remaining 201 were killed on the routes of other aid convoys.
The GHF uses private US security and logistics companies to get supplies into Gaza, largely bypassing a UN-led system that Israel alleges has let Hamas-led militants loot aid shipments intended for civilians. Hamas denies the allegation.
The GHF, which began distributing food packages in Gaza in late May after Israel lifted an 11-week aid blockade, previously told Reuters that such incidents have not occurred on its sites and accused the UN of misinformation, which it denies.
The GHF did not immediately respond to a request for comment on the latest UN figures.
"The data we have is based on our own information gathering through various reliable sources, including medical human rights and humanitarian organisations," Thameen Al-Kheetan, a spokesperson for the UN Office of the High Commissioner for Human Rights, told reporters in Geneva.
The United Nations has called the GHF aid model "inherently unsafe" and a violation of humanitarian impartiality standards.
The GHF said it had delivered more than 75 million meals to Gaza Palestinians since the end of May, and that other humanitarian groups had "nearly all of their aid looted" by Hamas or criminal gangs.
The Israeli army previously told Reuters in a statement that it was reviewing recent mass casualties and that it had sought to minimise friction between Palestinians and the Israel Defence Forces by installing fences and signs and opening additional routes.
The UN Office for the Coordination of Humanitarian Affairs has previously cited instances of violent pillaging of aid, and the UN World Food Program said last week that most trucks carrying food assistance into Gaza had been intercepted by "hungry civilian communities".
Separately, an Israeli scheme to move hundreds of thousands of already uprooted Palestinians to a so-called "humanitarian city" in Gaza has led politicians to spar with the defence establishment, but officials say a practical plan has yet to be crafted.
Even without a clear blueprint, opposition critics have denounced the proposal, with some likening the suggested site to a "concentration camp", which could lead to ethnic cleansing in the coastal enclave devastated by 21 months of conflict.
Prime Minister Benjamin Netanyahu's administration has defended the project, saying it would offer civilians a safe haven while further weakening Hamas militants' grip on Gaza, but it remains unclear whether it is a concrete government policy.
The idea was floated by Defence Minister Israel Katz earlier this month and Netanyahu convened minister and defence officials to discuss it late on Sunday.
The military had been asked to put together a detailed proposition, but Netanyahu dismissed it as far too costly and complicated, two Israeli officials who were present said, and ordered them to come up with something cheaper and faster.
An Israeli military source said it was a complex initiative that required intricate logistics for infrastructure such as sewage, sanitation, medical services, water and food supplies.
Planning was in a very initial phase only, the source said, and the goal was to help Palestinians who do not want to live under Hamas rule.
Hamas did not respond to a request for comment.
