The Popular Resistance Committees said Thursday that it blamed Israel for hiring hitmen to kill Rayid Nahal, the commander of its armed faction in the northern Gaza refugee camp of Ashati.
Nahal was gunned down in his car earlier Thursday when he traveled with his wife in the Gaza Strip.
Meanwhile, IDF forces raided the West Bank city of Nablus and killed a leader of the Al Aqsa Martyrs' Brigades, witnesses said.
The force entered the Old City of Nablus after 2 a.m. and ambushed a group of fighters, killing the leader, Fadi Kafishe, and wounding six other people in a gunbattle, witnesses said.
The army said it was on a routine operation in Nablus when gunmen fired at the troops, who returned fire, hitting one person.
Also on Thursday, a barrage of five Kassam rockets hit the southern town of Sderot on Thursday morning. According to Channel 10, several people suffered from shock.
Meanwhile, IDF soldiers who had been conducting an operation to uncover tunnels and explosives began withdrawing from the outskirts of Gaza City on Thursday, the army said.
The troops, who first raided the Shajaiyeh neighborhood late Saturday, killed a total of 18 Palestinians, the vast majority of whom were terrorists, in airstrikes and gunbattles, Palestinian emergency officials said.
The army released footage and photos Wednesday of what it described as a tunnel dug by militants from Shajaiyeh to the Karni crossing, the main cargo crossing between Gaza and Israel.
The tunnel, which was 13 meters (yards) deep and 150 meters (yards) long and was reinforced with wooden beams, was to be used for an attack on Israeli soldiers at the crossing, the army said.