Gaza civil defence official Mohammad al-Mughayyir said Israeli strikes and gunfire killed at least 52 people on Friday.
Mughayyir said the Palestinians killed included five who were shot while waiting for aid near a US-run site near Rafah in southern Gaza and several who were waiting for aid near the Wadi Gaza Bridge in the centre of the territory.
They were the latest in a spate of deaths near aid distribution centres in the devastated territory, which UN agencies have warned is on the brink of famine.
At Nasser hospital in Khan Yunis, crowds mourned 16 people killed on Thursday by what the civil defence agency said was shooting close to a nearby aid centre.
"I lost my brother in the American distribution centre that they set up to feed people," cried one mourner, Narmin Abu Muammar.
"They are killing people, not feeding them."
Medical aid charity Doctors Without Borders said Abdullah Hammad, who recently finished a contract working for it, was among those killed in Thursday's shooting.
It said he was the 12th colleague the group had lost in the Gaza war.
"We demand an end to this bloodshed," MSF said in a statement.
The US- and Israeli-run Gaza Humanitarian Foundation has denied multiple reports of incidents near its aid sites, but video has emerged showing American GHF staff shooting at Palestinian aid seekers.
The civil defence official told AFP that eight people, including a child, were killed in an Israeli air strike on the tents of displaced civilians near Khan Yunis.
Mughayyir said eight more people were killed in two other strikes on camps on the coast, including one that killed two children early Friday.
Israel's attacks in Gaza have killed at least 57,268 people in Gaza, according to the devastated territory's health ministry.