The strikes hit multiple homes overnight and into Thursday, killing men, women and children as they slept.
Israel resumed heavy strikes on Tuesday, shattering a ceasefire that had halted the war and facilitated the release of more than two dozen hostages.
Israel blamed the renewed fighting on Hamas because the militant group rejected a new proposal that departed from their signed agreement.
More than 400 Palestinians were killed on Tuesday alone, mostly women and children, according to Gaza's health ministry.
There have been no reports of Hamas firing rockets or carrying out other attacks.
The Israeli military said it intercepted a missile launched by Yemen's Iran-backed Houthi rebels early on Thursday before it reached Israeli airspace. No injuries were reported.
It was the second such attack since the US began a new campaign of air strikes against the rebels earlier this week.
One of the strikes early on Thursday hit the Abu Daqa family's home in Abasan al-Kabira, a village just outside of Khan Younis near the border with Israel.
It was inside an area the Israeli military had ordered be evacuated earlier this week, encompassing most of eastern Gaza.
The strike killed at least 16 people, mostly women and children, according to the nearby European Hospital, which received the dead.
Those killed included a father and his seven children, as well as the parents and brother of a month-old baby who survived along with her grandparents.
"Another tough night," said Hani Awad, who was helping rescuers search for more survivors in the rubble.
"The house collapsed over the people's heads."
On Wednesday, Israeli ground troops advanced in Gaza for the first time since the ceasefire took hold in January, seizing part of a corridor separating the northern third of the territory from the south.
Israel, which has also cut off the supply of food, fuel and humanitarian aid to Gaza's roughly two million Palestinians, has vowed to intensify its operations until Hamas releases the 59 hostages it holds - 35 of whom are believed dead - and gives up control of the territory.
The Trump administration, which took credit for brokering the ceasefire, says it fully supports Israel.
Hamas has said it will only release the remaining hostages in exchange for a lasting ceasefire and a full Israeli withdrawal from Gaza, as called for in the ceasefire agreement they reached in January after more than a year of mediation by the US, Egypt and Qatar.
Hamas, which does not accept Israel's existence, says it is willing to hand over power to the Western-backed Palestinian Authority or a committee of political independents but will not lay down its arms until Israel ends its decades-long occupation of lands the Palestinians want for a future state.
There was no immediate comment from the Israeli military on the latest strikes.
The military says it only targets militants and blames civilian deaths on Hamas because it is deeply embedded in residential areas.
The European Hospital in the southern city of Rafah said it received 36 bodies after the overnight strikes, mostly women and children.
The Nasser Hospital in Khan Younis said it received seven and transferred four to European, which were included in its count.
In northern Gaza, the Indonesian Hospital said it had received 19 bodies.
The war began when Hamas-led militants stormed into southern Israel on October 7 2023, killing some 1200 people and taking 251 hostage.
Most of the hostages have been freed in ceasefire agreements or other deals.
Israeli forces have rescued eight living hostages and recovered the bodies of dozens more.
Israel's retaliatory offensive has caused vast destruction in the territory, displaced hundreds of thousands of Palestinians and killed nearly 49,000 people, according to the Gaza health ministry.
It does not say how many were militants, but says more than half of those killed were women and children.
Israel says it has killed about 20,000 militants, without providing evidence.
with DPA
19°C