Hundreds of families fled their homes in the northern suburbs of the Burundian capital, Bujumbura, as factions of the rebel Forces nationales de libération (FNL) clashed, leaving 20 fighters dead.

"The clashes took place at Mugaruro where one of FNL wings opposed to [Agathon] Rwasa [FNL leader] has retreated into a small forest," the administrator of Buterere commune, Moise Ndayisenga, said on 3 September.

Other witnesses heard heavy gunfire and bomb blasts near the capital, as the fighting started early in the morning. They also saw bodies in the bushes.

Ndayisenga said residents and local administrators had been urging the FNL factions to move away from the area, pending their assembly for demobilisation or integration.

"Since 18 August, we have made several appeals that we do not want any armed groups in our commune, but our call was neglected and here is the result," he said.

According to residents, the fighters often harass them. "We are often beaten and our property is taken away," one resident said. "We need forces to protect us, so that we do not get caught between two fires."

The clashes were the latest manifestation of tension within the FNL. Two years ago, a breakaway faction accused Rwasa of gross human-rights violations.

Recently, the FNL walked out of a ceasefire monitoring team set up after it signed a truce with the government in September 2006. The team was to start work in February but it has been delayed by the wrangles.

Last week, the Burundi peace mediator and South African security minister Charles Nqakula said the Joint Verification and Monitoring Mechanism would be relaunched soon so that the country's peace process could be concluded by the end of the year.

A week ago, clashes again occurred at Buterere, and the faction opposed to Rwasa criticised the FNL leader for not making any effort to help implement the ceasefire accord with the government.

Army spokesman Lt-Col Adolphe Manirakiza said government forces were keeping out of the conflict to avoid appearing to take sides, but FNL spokesman Pasteur Habimana said the government had created a faction in the FNL in order to force a return of combatants who have remained in the Democratic Republic of Congo when the movement returned to Burundi in 2003.