Israeli forces are intensifying their attacks on the outskirts of Gaza City, residents say, as the military steps up preparations for a ground offensive to conquer it.
Hospitals said women and children were among more than 30 Palestinians killed in Israeli strikes in the city on Wednesday, most of them in the north and west.
The Israeli military's chief of staff vowed to continue striking Hamas's centres of gravity until it is defeated and its hostages freed.
The UN and aid groups said the Israeli operations were already having horrific humanitarian consequences for displaced families sheltering in the city, which is home to a million people and where a famine was declared last month.
Meanwhile, Israeli protesters took part in what they called a day of disruption to press their government to immediately agree a deal that would end the war in return for the release of all 48 Israeli and foreign hostages in Gaza, 20 of whom are believed to be alive.
Hospital officials said Israeli strikes and gunfire across the Gaza Strip had killed at least 46 people since midnight. Gaza City's Shifa hospital said it had received the bodies of 21 people, including five killed when an Israeli warplane targeted an apartment in the western Fisherman's Port area.
One of the strikes killed the parents and two sisters of three-year-old Ibrahim al-Mabhuh, his grandmother said. Umm Abu al-Abed Abu al-Jubein told Reuters news agency that she had found him buried underneath the rubble of a destroyed column in the home where the displaced family from the nearby town of Jabalia had been sheltering.
The military has told them to head to the al-Mawasi area, saying medical care, water and food will be provided. However, the UN has said the tent camps there are overcrowded and unsafe, and that southern hospitals are operating at several times their capacity.
Protests are growing in Israel as families of hostages demand a swift resolution to the ongoing conflict. Prime Minister Benjamin Netanyahu's commitment to conquer Gaza amid spiraling violence has intensified fears about the fate of those still held captive by Hamas.
Since the commencement of the ongoing military campaign after the attacks on southern Israel in October, the toll in Gaza has surged with reports indicating a catastrophic humanitarian situation.