Doctors on Sunday said 28 people were killed and around 60 people injured when the demonstration descended into a gunfight. The clashes started on Saturday when a group of civilians attacked the Shield of Libya headquarters in Benghazi. The organization is a group of rebels who had fought to oust former Libyan dictator Moamar Gadhafi.

Now, the Shield of Libya serves a semi-official role in the Libyan army. In an interview with Libya's Lana news organization, armed forces spokesman Ali al-Shikhi said the Shield of Libya was a "reserve force" of the Libyan army, and an attack on them was equivalent to an "attack on the legitimate authorities."

Prime Minister Ali Zeidan said on national television following the riot that the army had taken over the barracks of the Shield of Libya, including its stores of heavy weapons. He announced an enquiry into the violence.

A spokesman for the Shield of Libya said on Al-Ahrar television that armed aggressors had infiltrated a peaceful demonstration in front of the Shield of Libya.

A number of rebel groups continue to exist in Libya two years after the fall of Gadhafi. Libyan authorities face difficulty in either forcing them to disband or integrating them as part of the regular armed forces.

NATO has announced it will send a team to Libya this week to investigate the possibility of providing training to Libya's armed forces.

mz/msh (dpa, AFP, Reuters)