Two people were killed when gunmen briefly opened fire in Leba**n's largest Palestinian refugee camp, breaching a tense ceasefire, Palestinian sources said on Thursday. A source from the Fatah Palestinian faction said a Fatah official and a civilian had been killed in fire by "unidentified gunmen" overnight in Ain al-Hilweh in southern Leba**n. The breach threatened a ceasefire that ended several days of clashes between Fatah and an Islamist group in the camp.