(Adds details, dead boy)
GAZA, Aug 18 (Reuters) - An Israeli air strike killed the leader of an armed Palestinian faction, a top lieutenant and three other members in the southern Gaza Strip on Thursday, the group said, hours after Israel blamed gunmen from the territory for cross-border attacks.
The Popular Resistance Committees (PRC), a faction that often operates independently from Gaza's Islamist Hamas rulers, identified their dead leader as Kamal al-Nairab and said their military chief, Immad Hammad, had also been killed.
A sixth fatality in the attack on Rafah town was a nine-year-old boy who had been in the same house as the militants, local Palestinians said.
Hours earlier, gunmen killed seven people in a triple attack in southern Israel. Israel said the gunmen had come from Gaza through neighbouring Egypt, a charge denied by Hamas.
"The Israeli military is already taking action against the head of the Committees in Gaza," Defence Minister Ehud Barak told reporters at the site of the gun attacks. (Reporting by Nidal al-Mughrabi; Writing by Dan Williams; editing by Crispian Balmer)