Armed men clashed with Libyan defence ministry forces on Saturday in a suburb of Tripoli, which was marking one year since the killing of ousted leader Moamer Kadhafi, a military official said.
"An unknown group opened fire on the barracks; our forces are now dealing with the situation," Colonel Ali al-Sheikh told AFP.
The chief of staff spokesman said the clashes erupted in a suburb west of the Libyan capital. There were no immediate reports of casualties.
Witnesses said the road leading to the barracks, was closed to traffic and that gunshots could be heard near the military site.
The violence came exactly one year after Kadhafi, who ruled Libya with an iron grip for more than four decades, was captured by NATO-backed fighters and killed in his hometown of Sirte.