Fighter jets carried out more raids across the Gaza Strip in response to the firing for the first time in months of a rocket towards the Israeli town of Ashkelon, the Israeli army announced.
By Al Jazeera's estimate, the death count from Thursday's Gaza raids was nine, with at least 37 more wounded.
Even as the Israeli operations were continuing, the toll was already grim on the Palestinian side.
In Gaza, brothers Ahmad Fayyad, 20, and Sami Fayyad, 25, both members of the Islamic Jihad group, were killed in a raid on a house which also killed their mother, Karima, 50, and sister Asmaa, 20, medics said.
Separate gun battles with Israeli soldiers left one member of the armed wing of Hamas dead.
Describing some of the raids, Al Jazeera's correspondent in Gaza said: "Israeli helicopters fired at least two missiles at a position manned by the Qassam Brigades to the west of Rafah, wounding four Palestinians.
|Injured Palestinians received medical attention |
at a hospital in Khan Yunis on Thursday [AFP]
"Another air raid targeting the Shujaiya neighbourhood of eastern Gaza killed one Palestinian and wounded three others.
"This attack was preceded by Israeli bombing of three houses owned by commanders of al-Quds Brigades, two in Gaza, one in Rafah."
Quoting witnesses agencies also reported that Israeli jets destroyed two houses where fighters were suspected to have been hiding, while a third house was blown up by Israeli ground troops.
Three unidentified bodies were found in the rubble of one of the buildings, medics said.
An Israeli army spokeswoman said ground forces were engaged in heavy exchanges of fire with Palestinian fighters who were hiding in houses, saying civilian casualties were caused because "they were letting militants into their homes".
Later on Thursday, Israeli jets destroyed the home in central Gaza of an Islamic Jihad fighter who was killed in December, causing a massive explosion but no casualties, the spokeswoman said.
Separately, Israeli jets bombed a warehouse in Gaza City belonging to the Islamic Jihad and a building used by Hamas in the south of the territory.
No casualties were reported in either of the strikes.
The army said the air raids came in response to rocket fire against southern Israel, shortly after fighters fired a Grad-type 122mm rocket that struck the outskirts of Ashkelon, without causing casualties.
The Popular Front for the Liberation of Palestine - General Command (PFLP-GC), a Damascus-based movement led by Ahmed Jibril, which rarely operates in Gaza, said it fired the rocket.
West Bank incursion
In the Nablus operation, Israeli soldiers in about 70 military jeeps moved into the city centre and surrounded buildings, including the Rafidya hospital, in a hunt for wanted fighters, a Palestinian official said.
Three senior members of the Al-Aqsa Martyrs' Brigades, an armed offshoot of Fatah, were arrested and 24 Palestinians wounded during the raid, security sources said.
The West Bank-based government of Salam Fayyad has in recent months deployed hundreds of policemen as part of an ambitious security plan in its power base.
Although it supports the Palestinian prime minister's security plan, Israel has nevertheless reserved the right to operate inside towns and villages in the occupied territory to counter armed activity.