One man was killed and three people were wounded in a gun battle between militant Palestinians and members of a Lebanese leftist party.
The gun battle between the Palestinian Jund al-Sham group and the Lebanese Nasserite Popular Organization took place on the fringe of the Ein el-Hilweh refugee near the southern Lebanese city of Sidon.
The camp is the largest of Lebanon's 12 refugee settlements for Palestinians.
The Lebanese army, which maintains checkpoints outside the camp, did not intervene, witnesses said.
Lebanon's army does not enter the camp, which is home to about 75,000 Palestinian refugees and their descendants, who were displaced by the 1948 Arab-Israeli war.
The disarmament of Palestinian factions in Lebanon was discussed last week when Lebanese Prime Minister Fuad Saniora met Palestinian leader Mahmoud Abbas in Paris.