(KUNA) -- Dozens of mortar shells targeted the headquarters of Palestinian Preventive Security in Tal Al-Hawa, west Gaza City Friday evening, Palestinian sources said. Four personnel of the headquarters were injured in the attack and were hospitalized. Militants also attacked with RPG launchers the house of Director General of Internal Security Rashid Abu-Shibak in Al-Rimal district, south Gaza. The house was damaged in the attack but no casualties were reported by the police sources.Meanwhile, Palestinian medical sources said the death toll of the renewed clashes between Palestinian ruling Hamas movement and Fatah faction in north Gaza Strip Friday rose to 12. The personnel of the Hamas-led Executive Force surrounded the house of Mansour Shalayel, a leading activist of rival Fatah Movement in Jabaliya refugee camp earlier this evening. When the Fatah-led Presidential Guards stepped in to lift the siege on Shalayel a gun battle erupted, leaving Shalayel's brother and nephew killed and several others injured, according to eyewitnesses. The siege on Shalayel's house has ended later tonight.