A weekend of clashes in Libya has left at least two people dead and more than 40 injured.
Rival armed groups fired rockets and heavy machine guns around the town of Gharyan, about 80km south of the capital Tripoli.
The interim government had been trying to broker a ceasefire, but failed.
Officials told the BBC they were powerless to control some of their own revolutionary brigades who were trying to disarm pro-Gaddafi militias.
In hills surrounding Gharyan there have been scenes rarely witnessed in Libya since the capture and killing of Colonel Muammar Gaddafi nearly three months ago.
Revolutionary forces are again in position, their anti-aircraft guns mounted on the backs of pick-up trucks pointing west towards the town of Assabia.
The fighting began on Friday and continued sporadically throughout the weekend.
On Saturday, Libyan Defence Minister Osama al-Juweili travelled to the town to try to broker a ceasefire, but this did not hold.
Local officials in Gharyan told the BBC that militia groups in Assabia remained loyal to Colonel Gaddafi and should be disarmed - by force if necessary.
On Sunday, a delegation of tribal elders arrived in the town in an attempt to mediate in the dispute and to negotiate a prisoner exchange. But the stand-off continues on Monday and the situation remains tense.
Libya's interim government wants various armed groups to hand in their weapons, giving them the option of joining a national army, but it has met with only partial success.