Israeli war planes carried out four strikes, killing three people, including a school boy and a 60-year-old man, who medics said was a civilian.
The bloodshed erupted on Friday afternoon when an Israeli strike killed the leader of the Popular Resistance Committees (PRC), sparking a sharp cross-border exchange, in which 15 Gazans were killed, and more than 100 rockets were fired at Israel.
It was the deadliest 24-hour period in and around Gaza for more than three years.
The toll in Gaza yesterday stood at 18 dead and 30 injured, Palestinian medics said. Four people in Israel were injured by rockets.
The United States and the European Union have called on both sides to calm the situation, but efforts by Gaza’s Hamas rulers to broker an end to hostilities through Egyptian mediators have not yet borne fruit.
The latest fatalities included 12-year-old Ayub Asaliya, killed on his way to school in Jabaliya refugee camp, and 60-year-old Adel Saleh al-Issi. There were no details on a third fatality.
Israel said the campaign aimed to end rocket fire on the south of the country, though they said Friday’s assassination targeted a leader planning an imminent attack via the Sinai Peninsula.
Defence ministry figures said that militants had fired 124 rockets at Israel since Friday, including 68 Qassams and 44 longer-range Grads.
In response, the air force carried out 26 air raids, 15 of which targeted militants in the act of firing on Israel, the ministry said.
The Iron Dome air defence system set up around the southern cities of Ashdod, Ashkelon and Beersheva intercepted 30 rockets, it said.
Two more Grad rockets hit the desert city of Beersheva during the afternoon, police said, with one landing in a school playground.
Of those killed in Gaza, 10 were militants from the radical Islamic Jihad movement, while another five were from the PRC, including the group’s leader, Zuhair al-Qaisi, who died in the first strike on Friday.