Rival Palestinian factions clashed in a refugee camp in northern Lebanon on Monday, shaking the camp with explosions and wounding at least two gunmen, officials at the camp said. The gunbattle between Fatah Islam and Fatah Uprising started after an argument between members of the two groups in the Nahr al-Bared camp near the northern city of Tripoli, said Palestinian officials in the camp. The fighting lasted less than 30 minutes, wounding a fighter from each group, the officials said, speaking on condition of anonymity for security reasons. The Fatah Islam member was seriously wounded. But within several hours, clashes resumed in the evening. Residents said they could hear explosions, though the cause was not known.