One person was killed when heavy clashes erupted Monday between rival Palestinian factions in a refugee camp in southern Lebanon, Lebanese and Palestinian sources said.

They said the clashes were between members of the mainstream Fatah movement and members of a fundamentalist group called Jund al Sham, one of whose members was killed.

The militants exchanged machinegun fire and rocket-propelled grenades and people were seen fleeing the streets.

Jund al-Sham has in the past clashed with Fatah inside the camp, which is the largest of Lebanon's 12 Palestinian refugee camps and regarded as a hotbed of Islamic extremists.

Jund al Sham, believed to have first appeared in Afghanistan in 1999, was established by Syrians and Palestinians with links to Abu Musab al-Zarqawi, who founded al-Qaeda in Iraq and was subsequently killed by a US airstrike.