Tripoli international airport came under rocket fire on Wednesday for a fourth straight day, in attacks aimed at ousting anti-Islamist fighters who control the facility, a Libyan security official said.
"The airport was again targeted by mortar fire and rockets for several hours," the official said, asking not to be named.
An AFP photographer said the bombing sparked fires around the airport, setting ablaze a cargo plane on the tarmac and a customs warehouse, sending firefighters into action.
Islamist militias have since Sunday unleashed dozens of rockets at Tripoli airport, damaging around a dozen planes and closing down Libya's main air link with the outside world.
An airport official said on Wednesday that the facility, controlled by liberal ex-rebels from Zintan, southwest of the capital, would probably remain shut for "several weeks, if not months".
The Zintan fighters, in control of the airport for the past three years, have deployed armoured cars and pickups on access roads to head off any ground attack.
On Monday, the airport in the country's third city Misrata was also forced to shut down because it is linked to the control tower in Tripoli.
But flights resumed on Tuesday night at Misrata and also at Miitiga military airport in the suburbs of Tripoli, allowing Libyans stranded at airports around the world to return.
With liberal and Islamist militias locked in a deadly power struggle, the Libyan government has said it is considering calling for international forces to help restore security.
Nato warplanes helped topple dictator Muammer Gaddafi in a 2011 revolution, sparking a power struggle between rival armed groups that has wracked the North African country ever since.