Live updates: Follow the latest on Israel-Gaza
At least 25 Palestinians were killed in strikes across Gaza that largely targeted refugee camps overnight on Saturday and into Sunday afternoon.
Fifteen were killed in Israeli attacks on homes and commercial buildings sheltering displaced people in Bureij refugee camp and in Khan Younis, the official Wafa news agency reported.
At least two people, including a child, were killed in strikes on Nuseirat refugee camp on Sunday morning.
An attack on a multistorey residential tower in the camp wounded at least five people, Wafa added, describing "intense" bombardment on the camp.
Footage on social media showed the building being bombed as drones flew overhead.
Artillery shelling was reported near the camp's power station and "all kinds of missiles" were fired from drones, sources told Wafa.
Eight people were later killed in attacks on Bureij, Rafah and Khan Younis, Wafa reported.
About 39,000 Palestinians have been killed and 90,000 wounded across the enclave since the war began in October.
Sixty-four people were killed across the enclave in 24 hours this weekend, Gaza's Health Ministry said in a daily update on Sunday afternoon.
Hundreds have also been killed in the occupied West Bank and in Lebanon, where Israel has bombed the south on a daily basis since border clashes with Hezbollah began, also in October.
The latest strikes come as Israeli Prime Minister Benjamin Netanyahu prepares for a controversial visit to Washington, where he will address Congress on Wednesday.
Mr Netanyahu, expected to soon be the subject of an International Criminal Court arrest warrant, will fly to the US on Monday evening, before meeting President Joe Biden on Tuesday.
He was initially scheduled to depart for Washington on Sunday evening.
Israelis gathered on Saturday to stage more anti-government protests, calling on the Prime Minister to approve a ceasefire deal with Hamas before leaving for the US.
Mr Netanyahu will meet the negotiating team on Sunday afternoon, Israel's Kan public broadcaster reported, claiming efforts are intensifying to agree on a deal before his departure.
Demonstrators are expected to hold protests in Washington during his visit.
More than 200 congressional staff signed a letter last week urging politicians to boycott Mr Netanyahu's address.
“Citizens, students and lawmakers across the country and the world have spoken out against the actions of Mr Netanyahu in his war on Gaza,” it read.
“Israelis have been protesting in the streets for months, decrying his failure to negotiate a ceasefire and release of hostages. We hope you will join your fellow members of Congress in protest at his speech or in refusing to attend it.”
