A roadside bomb killed a senior official in the Palestinian Fatah faction and four other people in southern Lebanon on Monday, security sources said.

Kamal Medhat, deputy head of the Palestine Liberation Organisation in Lebanon, was killed with his companions on a road near Mieh Mieh camp outside the southern city of Sidon.

The bomb, hidden under a manhole cover in the road, flipped one car off the road and badly damaged another. Television footage showed debris ablaze in a field.

Palestinian President Mahmoud Abbas condemned Medhat's killing as an act of terrorism. A Fatah spokesman in the West Bank said it was too early to speculate on who was behind the attack and that the Palestinian leadership would await the findings of investigations by the Lebanese security forces.

Describing the attack as an "assassination", Fatah spokesman Fahmy al-Zaarir in the West Bank told Reuters that Medhat had been accompanying the PLO chief in Lebanon, Abbas Zaki, on a visit to the Mieh Mieh refugee camp but that Zaki was uninjured.

"A bomb was planted by the road and it exploded when the car passed that was carrying Kamal Medhat to the camp for a reconciliation meeting between families," Zaarir said, referring to efforts to resolve a dispute between rival clans in the camp.

He said it was too early to speculate on who was behind the attack and that the Palestinian leadership would await the findings of investigations by the Lebanese security forces.

Another source, Munir Maqdah, who is in charge of security at Lebanon's 12 refugee camps, told AFP, "Kamal Medhat was killed along with four of his bodyguards when a roadside bomb exploded as his convoy drove by, near the entrance to the camp."

Palestinian President Mahmoud Abbas condemned the killing as an act of terrorism. "President Abbas condemns the terrorist crime that targeted Major General Kamal Medhat," he said in a statement issued by his office. It said two of Medhat's bodyguards also died.

The statement added: "He dedicated his life to serve his people and his cause."

Tensions have been high in Mieh Mieh and the nearby Palestinian camp of Ain al-Hilweh, where Fatah and a range of Islamist factions compete for influence.

Two people, including a Fatah activist, were killed on Saturday in a gunbattle in Mieh Mieh camp. The clash was attributed to a family dispute.

Medhat was the deputy head of the Palestine Liberation Organisation in Lebanon, which is home to 12 Palestinian refugee camps that house more than 200,000 registered refugees.