Fighting has raged on Tripoli's doorstep since Libyan strongman Khalifa Haftar launched an offensive in April to seize the capital, the seat of the UN-recognised Government of National Accord (GNA).

Flights were halted twice on Monday, according to Mitiga airport's Facebook page, but were operating again on Tuesday.

Several planes were diverted to Misrata, 200 kilometres (124 miles) east of Tripoli, during the first suspension which lasted for several hours in the afternoon after shelling near the runway.

In the evening, the airspace was "closed again and passengers already on board planes disembarked because of another series of rockets", the airport management said.

It was unclear who was behind the attacks.

Addressing the UN Security Council by video link from Tripoli on Monday, UN envoy Ghassan Salame expressed "alarm" about the frequent attacks that have shaken the capital's only functioning airport.

He said several "have come perilously close to hitting civilian aircraft with passengers on board".

"I am afraid that with the almost daily bombardment, luck will run out," Salame said, according to the UN website.

"I call upon the authorities in Tripoli to cease using the airport for military purposes and for the attacking forces to halt immediately their targeting of it".

The capital's main airport was destroyed in fighting in 2014.

Mitiga airport is on a former military base on the city's outskirts and has been forced to close several times because of clashes.