(Gunfire) A lookout spot in Tripoli where rival militias are in a gunbattle that has injured at least five people.

When a bullet pierce this window at a nearby hospital -- it sent doctors and nurses running for cover.

Officials say the fighting started after midnight and escalated after a rocket-propelled grenade (RPG) was fired into one of the group's headquarters

Libya's rulers have struggled to control semi-official armed groups who are competing for power and outgun the police and army in the north African country a year after Gaddafi's fall.