At least 19 Palestinians have been killed as a result of Israeli ground fire and air strikes in Gaza early on Sunday, medics said as troops pushed deeper into the Hamas-run territory, AFP reported.
Eighteen people were killed around Jabaliya and Beit Lahiya in the north and one near Khan Yunis in the south, they said.
The identities of all the victims were not immediately available, but civilians were among the dead, they added.
Israel unleashed a massive bombardment of Hamas targets in Gaza on December 27 in response to militant rocket and mortar fire, and sent in ground troops a week later.
Since the start of "Operation Cast Lead" at least 485 Palestinians have been killed, including 80 children, and more than 2,400 wounded in Gaza, according to Gaza medics.
Rockets fired by Gaza militants have killed three civilians and one soldier inside Israel during the same time period.
Since the start of the ground offensive 30 Israeli soldiers have been wounded, two of them seriously, the army said.
Palestinian medics said "several" Hamas fighters had been seriously wounded, but that ambulances were unable to get to them as firefights raged.