The Gaza Health Ministry reported that the death toll has risen to 43 in the Strip, including 13 minors, APA reports citing Haaretz.
There are currently 269 wounded. Six were killed in Israel.
Hostilities between Israel and Hamas escalated overnight, with 35 Palestinians killed in Gaza and five in Israel in the most intensive aerial exchanges for years.
Israel carried out hundreds of air strikes in Gaza into the early hours of Wednesday, as the Islamist group and other Palestinian militant groups fired multiple rocket barrages at Tel Aviv and Beersheba.
One multi-story residential building in Gaza collapsed and another was heavily damaged after they were repeatedly hit by Israeli air strikes. Israel said it attacked Hamas targets, including intelligence centres and rocket launch sites.
It was the heaviest offensive between Israel and Hamas since a 2014 war in Gaza, and prompted international concern that the situation could spiral out of control.
Hamas's armed wing said it fired 210 rockets towards Beersheba and Tel Aviv in response to the bombing of the tower buildings in Gaza City
In Tel Aviv, air raid sirens were heard around the city. For Israel, the militants' targeting of Tel Aviv, its commercial capital, posed a new challenge in the confrontation with the Islamist Hamas group, regarded as a terrorist organisation by Israel and the United States.
The violence followed weeks of tension in Jerusalem during the Muslim fasting month of Ramadan, with clashes between Israeli police and Palestinian protesters in and around Al-Aqsa Mosque, on the compound revered by Jews as Temple Mount and by Muslims as the Noble Sanctuary.