Rival groups armed with machine guns and rocket-propelled grenade launchers battled for hours Thursday inside a Palestinian military camp in a remote part of eastern Lebanon, killing one person, security officials said. The Ein al-Bayda camp is one of several bases run by Palestinian militant groups in Lebanon. Most of them are located in the eastern Bekaa Valley near the border with Syria, whose government supports the groups. The bases, which are separate from the country's Palestinian refugee camps, are illegal. Lebanese authorities, however, have left them be for fear that any clash with the groups could be explosive. Thursday's fighting was between rival Palestinian groups and lasted three hours, Lebanese security officials said. The camp is run by the Popular Front for the Liberation of Palestine-General Command. A senior military official said the fighting stopped after four militants -- three Palestinians and a Lebanese man -- handed themselves over to Lebanese troops. Lebanese forces were seen taking up positions near the base but did not intervene. Police officials said a member of the militant group was killed in the fighting. The security and military officials spoke on condition of anonymity in line with military regulations. 