Israeli strikes across the Gaza Strip killed at least 135 people overnight and into Sunday, hospitals and medics said, and prompted the main hospital in northern Gaza to close.
The health ministry in Gaza said that all public hospitals in the north of the territory were now "out of service" after Israeli forces besieged the Indonesian hospital.
"The Israeli occupation has intensified its siege with heavy fire around the Indonesian hospital and its surroundings, preventing the arrival of patients, medical staff, and supplies -- effectively forcing the hospital out of service," the ministry said.
"All public hospitals in the North Gaza governorate are now out of service," it added.
Israel has intensified its war in the territory that, after more than 19 months, shows no signs of abating.
Israel's military has said the expansion of its operations is aimed at "achieving all the war's objectives," including releasing hostages and "the defeat of Hamas."
The intensified assault comes as international concern has mounted over worsening humanitarian conditions in Gaza due to an Israeli aid blockade since March 2.
Civil defence spokesman Mahmud Bassal told AFP on Sunday that 22 people were killed and at least 100 others wounded in a predawn attack on tents sheltering displaced Palestinians in Al-Mawasi, in the southern Gaza Strip.
AFPTV footage showed people sifting through the wreckage of ruined shelters and rescuers treating the wounded.
At a hospital in nearby Khan Yunis city, young men mourned over the shrouded bodies of loved ones laid out on the ground outside.
In northern Gaza, Bassal said seven people were killed in a strike on a house in Jabalia, while the Al-Awda hospital in the same area reported damage.
Four more deaths were recorded in the central area of Al-Zawayda and in Khan Yunis in the south, according to Bassal.
He said that the "series of violent Israeli air strikes" across Gaza overnight and in the early morning resulted in a total of "at least 33 martyrs, more than half of whom were children."
There was no immediate comment from the Israeli military.
‘Ceasefire, now’
The announcement of Israel's stepped-up campaign drew international criticism on Saturday.
UN chief Antonio Guterres, addressing an Arab League summit in Baghdad, said he was "alarmed" at the escalation and called for "a permanent ceasefire, now."
The summit's final statement urged the international community "to exert pressure to end the bloodshed."
Italy urged Israel to stop the strikes, while Germany said it was "deeply concerned". European Council President Antonio Costa said he was "shocked by the news from Gaza."
Israel resumed its operations in the territory on March 18, ending a two-month truce in the war.
In Tel Aviv, demonstrators took to the streets on Saturday to protest against Prime Minister Benjamin Netanyahu's government and demand it strike a deal to secure the release of the remaining hostages.
"Instead of bringing them all home by agreeing to the deal that is on the table, Netanyahu is dragging us into a needless political war that will lead to the death of the hostages and soldiers," said protester Zahiro Shahar Mor, nephew of slain hostage Avraham Munder.
Doha talks
Senior Hamas official Taher al-Nunu said on Saturday that new talks on ending the war had begun in Doha "without any preconditions from either side."
Previous negotiations mediated by Qatar, Egypt and the United States failed to secure a breakthrough, but the talks have been ongoing.
Netanyahu's Likud party said he had been "in continuous contact" with the Israeli delegation and had ordered the negotiators "to remain in Doha for the time being."
Israel's far-right National Security Minister Itamar Ben Gvir argued against a deal, saying "now is not the time to pull back."
Israel has faced increasing pressure to lift its aid blockade, as UN agencies warn of critical shortages of food, clean water, fuel and medicine.
Marwan Sultan, director of the Indonesian Hospital in northern Gaza, said before closing down that the situation there was "catastrophic" amid nearby attacks and "a severe shortage" of supplies.
On Sunday, the health ministry in Hamas-run Gaza accused Israel of laying siege to the hospital, where it said "a state of panic and confusion is prevailing... severely hampering the provision of emergency medical care."
The Gaza health ministry said that at least 3,131 people have been killed since Israel resumed strikes on March 18, taking the war's overall toll to 53,272.