Clashes have broken out between Palestinian factions in a refugee camp in southern Lebanon.
Civilians were forced to flee amid Friday's violence
The fighting was between members of the Fatah faction and an Islamist group called Jund al-Sham.
It took place in the densely populated Ain al-Hilwe refugee camp, which is located on the outskirts of the southern city of Sidon.
Fighters launched rockets and exchanged gunfire in the middle of the camp, causing dozens of civilians to flee.
Lebanese and Palestinian officials said one Fatah member was killed and four others wounded, the Associated Press news agency reported.
Tension had been high following the arrest by Fatah on Thursday of Samir Maarouf.
He is a commander in the Jund al-Sham, a relatively small faction in the Palestinian camp, which is believed to have around 50 armed members.
Fatah handed Mr Maarouf over to the Lebanese army, accusing him of violence.
Formed in 2002, Jund al-Sham - literally the Army of Greater Syria - is a radical splinter group.
Its name refers to the area covering the modern states of Syria and Lebanon and the Palestinian territories - which the group says form one Muslim land.
The group has been blamed or claimed responsibility for a number of bombings and gun battles in Lebanon and Syria.
Last year it fought Lebanese troops after joining a revolt by fellow Islamic militant group Fatah al-Islam that was centred on the northern refugee camp of Nahr al-Bared.
Ain al-Hilwe is the largest of Lebanon's 12 Palestinian refugee camps, with a population of 70,000.
It is under Palestinian jurisdiction and off limits to the Lebanese authorities.
Palestinian security officials have been meeting inside the camp to try to restore order.