Haftar's self-styled Libyan National Army launched an offensive in April to try to wrest Tripoli from forces of the Government of National Accord which is based in the capital.

Pro-GNA forces have weathered the initial onslaught and since then fighting has remained deadlocked on the outskirts of the city, with both sides resorting to air strikes.

"The field hospital located on the airport road (south of Tripoli) was hit by an air raid. Five doctors were killed and seven other people, including rescuers, wounded," health ministry spokesman Lamine al-Hashemi said.

The strike occurred on Saturday and was carried out by "a Haftar warplane", he said.

"It was a direct hit against the hospital which was packed with medical teams," Hashemi added.

There was no immediate confirmation or denial of responsibility from Haftar's forces.

The attack was the third to target a hospital south of the capital.

On July 16 three doctors and a paramedic were wounded in a strike on the Swani hospital near the capital, the second time it was targeted.

The World Health Organization and rights groups have repeatedly called on both sides in the conflict to spare medical personnel, clinics and hospitals.

The fighting since April has left nearly 1,100 people dead and wounded more than 5,750, according to the WHO. More than 100,000 civilians have fled their homes.