At least 32 Palestinians seeking food have been killed by Israeli gunfire near two aid distribution points close to Khan Younis and Rafah in southern Gaza, according to the territory's Hamas-run health ministry.
Dozens were also injured near the two sites run by the controversial US and Israeli-backed Gaza Humanitarian Foundation (GHF), it said.
The GHF said there were no incidents "at or near" their sites, but that there had been "Israel Defense Forces (IDF) activity" hours before their sites were due to open.
One eyewitness told the Reuters news agency that the Israeli gunfire seemed "targeted to kill".
The Palestinian ministry of health said a number of bodies were taken to nearby Nasser hospital on Saturday morning.
There are almost daily reports of Palestinians being killed while seeking aid since the GHF began operations in late May. Witnesses say most have been shot by Israeli forces.
The IDF told the BBC that in the latest incident, troops fired warning shots to prevent "suspects" approaching them, saying the incident happened before the aid sites opened.
Mohammed Al-Khalidi, speaking to Reuters, pointed the finger at the Israeli army for the attack.
He said he was part of a group of Palestinians who had been told the GHF aid distribution centre was open, but when they arrived tanks began moving towards them and opened fire.
"It wasn't shots that were to scare us or to organize us, it was shots that were targeted to kill us, if they wanted to organize us they would have, but they meant to kill us."
The GHF uses private security contractors to distribute aid from sites in Israeli military zones. Israel and the US say the system is necessary to stop Hamas from stealing aid. The UN refuses to co-operate with it, describing it as unethical and saying no evidence has been offered of Hamas systematically diverting aid.
BBC.