A residential complex with several buildings in Shujaiyya (Shejaiya) in Gaza City was hit in the attack on Wednesday, according to the civil defense in Hamas-ruled Gaza.
There are still people trapped under the rubble, says spokesperson Mahmud Bassal to the news agency AFP.
Medical personnel report that more than half of the dead are women and children.
Dust and destruction filled the entire area. We couldn't see anything, only hear the screams and panic from the people, says 26-year-old eyewitness Ayub Salim to AFP.
According to Salim, who calls the attack "a massacre", the area was hit by several rockets and shrapnel "flying in all directions".
Israel's military, which last week issued an evacuation order for Shujaiyya, claims that the target of the attack was a high-ranking Hamas member. The person in question is not named.
The attack left a large area in ruins. In pictures taken by the Turkish news agency Anatolia, a small boy is seen being pulled out from under heavy concrete blocks in a pile of rubble. Large house facades are torn off and everything is gray, covered in smoke and dust. In another picture, a seemingly lifeless child is seen being wrapped in a blanket.
The hospital al-Ahli, where the wounded are being taken, is in urgent need of blood donations, reports the Qatar-based media company Al Jazeera.
On X the Israeli military's spokesperson Avichay Adraee states that Israel has attacked "more than 45 targets across the entire Gaza Strip" in the past 24 hours, including in Shujaiyya where terrorists are said to have been killed. At the same time, the Israeli ground offensive in Gaza continues, according to Adraee.