Palestinian news agency WAFA said 51 Palestinians, mostly women and children, were killed and scores wounded in an Israeli bombardment of Gaza's Maghazi camp on Saturday night.
Reuters could not independently verify the WAFA report.
The Israeli military did not immediately respond to a request for comment.
A spokesperson for the Hamas-run Health ministry in Gaza, Ashraf al-Qidra, said a large number of people were killed without giving an exact figure, adding scores of people with severe injuries were laying on the ground of a hospital's emergency ward.
Maghazi is located in the Deir al-Balah Governorate in the central Gaza Strip.
Israel says it is targeting Hamas, not civilians, and accuses the militants of using residents as human shields.
