Rival militias in an area south-west of the Libyan capital exchanged heavy gunfire on Monday after a dispute flared up between them that local residents said had killed at least four people.

The conflict, rooted in an old tribal rivalry, is one of the hundreds of faultlines running through Libyan society that have left the new rulers struggling to hold the country together since the overthrow of former leader Muammar Gaddafi.

Reuters journalists in Wamis, about 190 km (120 miles) from Tripoli, said the fighting was between members of the El-Mashasha tribe, based around the town, and fighters from the larger town of Zintan in the mountains to the north.

Shots, including from machine guns, could be heard and all men and boys in Wamis were carrying Kalashnikov rifles, they said.

The Reuters journalists were shown a school and a mosque which had been hit by artillery or rocket fire, and also saw evidence of shells or rockets landing between houses in a residential area.

Residents said three people had been killed in attacks on the town by fighters from Zintan over the past 48 hours.

They started shelling yesterday around lunch time, said Wamis resident Mohammed Suleiman. They have been attacking civilians, they are not attacking military targets ... we want a ceasefire.

However, a senior official from Zintan told Reuters that the dispute would soon be resolved.

It was a misunderstanding between the two sides, said Taha Omran Al-Turki, head of the Zintan local council. The information I received by telephone is that the situation is now quiet and the shooting has stopped.

RECONCILIATION TALKS

He said elders from both sides held a meeting in Tripoli on Monday at which Mustafa Abdel Jalil, head of Libya's National Transitional Council tried to broker an end to the dispute.

They said that, God willing, they will resolve the problem between Zintan and the El-Mashasha today or tomorrow.

The long-standing enmity between Zintan and the El-Mashasha worsened during the seven-month conflict against Gaddafi's rule.

Zintan rose up against Gaddafi while most of the El-Mashasha tribe supported him. Some of the artillery bombardment directed against Zintan during the conflict came from pro-Gaddafi batteries based in areas controlled by the tribe.

Local people said the latest flare-up began when El-Mashasha fighters killed a militia commander from Zintan on Sunday as his convoy tried to pass through a nearby town.

One local man said the commander was related by marriage to Osama Al-Juwali, the former head of Zintan's militia who was last month appointed as new Libyan defence minister.

An official in Zintan, who did not want to be identified, said El-Mashasha fighters had killed a family from Zintan on Monday as they drove through an area controlled by the tribe. This could not be independently confirmed.

(Additional reporting by Ali Shuaib, Hisham El Dani and Taha Zargoun in Tripoli; Writing by Christian Lowe; Editing by Louise Ireland)