Fresh clashes broke out Friday between rival Libyan militias battling for control of Tripoli airport, the target of 13 days of shelling that have disrupted air links to the outside world.

Fresh clashes broke out Friday between rival Libyan militias battling for control of Tripoli airport, the target of 13 days of shelling that have disrupted air links to the outside world.

Columns of smoke billowed into the sky around the airport perimeter, while loud explosions were heard throughout the morning, an AFP reported.

Libya's main international airport has been shut since fighting erupted on July 13, a bout of violence that has killed at least 47 people and wounded 120, according to the health ministry.

The clashes started with an assault on the airport by a coalition of groups which has since been backed by fighters from third city Misrata.

The attackers are battling to flush out fellow former rebels from the hill town of Zintan, southwest of Tripoli, who have controlled the airport for the past three years.