Gaza City (Palestinian Territories):  Eleven Palestinians, most of them fighters, were killed and around 15 wounded in a series of Israeli air strikes on the Gaza Strip, Palestinian medics said on Saturday.
The Israeli raids came as Palestinians fired dozens of rockets and mortar rounds into the Eshkol region of southern Israel, wounding four people, one seriously, Israeli military sources said.
One Israeli strike, on a car travelling in the Tel El-Hawa neighbourhood west of Gaza City, killed the head of the militant Popular Resistance Committees (PRC), Zohair al-Qaisi, and fellow member Mahmud Hanani, the group said.
Both the PRC and the military wing of Hamas threatened to retaliate for Qaisi's death, and around 40 rockets and shells were subsequently fired on southern Israel.
The Al Quds Brigades, the military arm of Islamic Jihad, said later that strikes on the east side of Gaza City and then on the city centre had killed nine of its members.
Around 15 Gaza citizens were wounded in the Israeli raids, emergency services said.
The Israeli attacks came in response to Palestinian mortar and rocket fire which started yesterday morning. The Israeli military said that in the course of the day about 40 rockets and mortar rounds had landed in southern Israel.
The PRC and the Al-Aqsa Martyrs Brigades, an armed offshoot of Palestinian president Mahmud Abbas's Fatah movement, issued statements claiming to have fired rockets into Israel on Friday.
The official Palestinian WAFA news agency quoted a statement by the Fatah-dominated Palestinian Authority condemning the Israeli retaliation, saying it had created a "negative environment" that would "escalate the circle of violence in the region."