At least 34 Palestinians have been shot dead near food distribution centres in Gaza, according to the health ministry.
It said 33 people were killed trying to reach a Gaza Humanitarian Foundation (GHF) centre near Rafah, while another person died heading to an aid hub in the central Gaza Strip.
Israeli troops had opened fire as they attempted to control the crowds early on Monday close to the Rafah site, two witnesses said.
The number of deaths in shootings was the highest reported daily total since the Israeli and US-backed aid centres opened in May, as thousands of Palestinians move through Israeli military-controlled areas to get to them.
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The ministry added on Monday that four other people who were not trying to reach distribution centres were killed elsewhere. It claims hundreds of Palestinians have been killed and hundreds more injured since the GHF centres opened.
The Israel Defence Forces (IDF) has not commented on the latest incident, but previously said its troops had fired warning shots at what it called suspects approaching their positions near GHF sites.
Heba Jouda and Mohamed Abed, two Palestinians who were in the crowd of thousands near the Rafah aid site, said Israeli troops started firing at around 4am.
Ms Jouda said: “Fire was coming from everywhere… It’s getting worse day by day.”
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UN: 500,000 are food insecure in Gaza
The International Committee of the Red Cross added in a statement that its field hospital had received around 200 injured people on Monday – the highest mass casualty event it has seen.
Speaking on Sunday, a GHF spokesperson said that “none of the incidents to date have occurred at our sites or during operating hours”.
They added the incidents have involved aid-seekers who were moving “during prohibited times… or trying to take a short cut,” and said it was trying to improve safety measures.
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It comes as Foreign Secretary David Lammy called on Israel to “show restraint” in its strikes on Iran, and warned military action will not end Tehran’s nuclear capabilities.
“Fundamentally, no military action can put an end to Iran’s capabilities,” he told MPs, adding that the government’s message to Israel and Iran is: “Step back, show restraint, don’t get pulled ever deeper into a catastrophic conflict whose consequences nobody can control.”