An Israeli air strike hit a house in central Gaza before dawn killing five family members, including two women and two children.
The air raid hit a family home, witnesses and medics said.
Doctors at the Al-Aqsa Hospital in Deir al-Balah said the five dead all came from the same family, a 28-year-old father, his 26-year-old wife and their two boys aged three and four.
The father's 45-year-old aunt was also killed, they said.
Four more Palestinians were killed in other strikes.
The Israeli military said it had carried out around 20 air strikes over Gaza early today.
They added that Gazan militants had fired more than 40 rockets at Israel, with no Israeli casualties were reported.
Three rockets or mortar rounds had hit southern Israel near the border with Gaza.
Hostilities in the six-week war between Israel and Gaza's Islamist de facto rulers Hamas resumed on Tuesday as Egyptian-brokered truce talks collapsed.
Emergency services say 81 people have died in the Palestinian enclave since then.
Yesterday, an Israeli child was killed and seven other people wounded, one of them critically, by mortar and rocket fire from Gaza.
At least 2,097 Palestinians have been killed since July 8, 70 percent of them civilians, according to the United Nations.
There have also been 68 people killed on the Israeli side, all but four of them soldiers.
Egyptian officials have called on both sides to halt fire and resume peace talks, with a senior Egyptian diplomat saying that Palestinain President Mahmoud Abbas has confirmed that Hamas are prepared to go to Cairo for further talks, although Hamas has not confirmed this report.
Israel has not yet made a comment on the invitation.
Rocket fired from Lebanon hits northern Israel
A rocket fired from Lebanese territory hit northern Israel, the army has said.
"The rocket that was fired from Lebanon hit the Upper Galilee," the army said in a statement, correcting a previous report that said the rocket had hit east of Acre.
There was no immediate claim of responsibility for the launch or reports of damage or injuries.
A Lebanese security source said the rocket was fired from Dheira, three kilometres from the border with Israel.
The same source noted that Israeli helicopters were seen flying around the border area.
In mid-July, at least nine rockets were fired from Lebanon at the Jewish state, prompting Israel to retaliate with artillery fire.
Lebanese military officials had at the time said they believed the attacks were carried out by a small Palestinian group in an act of solidarity with Gazan militants.