A car explosion outside a Gaza mosque has killed a top Palestinian militant.The attack triggered a gunbattle after fighters loyal to the victim accused Palestinian security forces of collaborating with Israel in the blast. Israel denied involvement in the strike, which also wounded a young boy. An umbrella group of militants in Gaza, the Popular Resistance Committees, accused Israel of working with local Palestinian officials. A spokesman said the group had “declared war” against Israel and former Gaza security chief and Fatah member Mohammed Dahlan. He also named other Palestinian officials.” The clashes came a day after a Palestinian suicide bomber killed four Israelis in the West Bank settlement of Kedumim. The al-Aqsa Martyrs Brigades, an offshoot of President Mahmoud Abbas’ Fatah group, has claimed responsibility. It is understood a young man posing as an Orthodox Jew hitch-hiking stopped acar and then blew himself up inside. He has been identified as a 24-year-old from Hebron.