Gaza’s Hamas-run health ministry says an Israeli air strike killed at least 70 people in the Al-Maghazi refugee camp in the centre of the strip.
A spokesman said the death toll was likely to rise given the large number of families living in the area.
The Israeli military said it was looking into reports of the strike.
It comes as Israeli and Arab media say Egypt, which borders the Gaza Strip, has put forward a new proposal for a ceasefire between Israel and Hamas.
Dozens of injured people were rushed from Maghazi to nearby Al-Aqsa Hospital with footage showing some children’s faces covered in blood and body bags piled outside.
The health ministry says three houses were hit in the attack late on Sunday.
According to ministry spokesman Ashraf al-Qudra, a densely populated residential block was destroyed.
A father said he had lost his daughter and grandchildren, adding that his family had fled from the north for safety in central Gaza.
The Palestine Red Crescent Society says “intense” Israeli air strikes have led to the closure of main roads between Maghazi and two other refugee camps, Al-Bureij and Al-Nuseirat, “hindering the work of ambulances and rescue teams”.
According to the health ministry, more than 20,000 people have been killed – mostly children and women – and 54,000 injured in Gaza since 7 October, when Hamas and other Palestinian groups attacked Israel, killing 1,200 people and taking about 240 hostages.
