The Tripoli International Airport, which handles about 30 flights in and out a day, has been shut down after it was attacked by "at least two dozen armed militiamen," according to the BBC. The airport has just two runways, but as the BBC explains, if you put the right weapons in the right places, you don't need that many people to shut down a country's largest passenger travel hub: "The brigade has placed a pick-up truck mounted with an anti-aircraft gun underneath each of the six planes on the tarmac, our correspondent says." The A.P. reports that flights are still reaching Libya, but they're being "diverted to Metiga air base in the city's center."

The militia fighters who stormed the airport demanded the release of their abducted leader, who they believed was being held there, Reuters reported. The Libyan Army is on the scene and witnesses have started reporting gunfire and photographing plumes of smoke rising from the airport:

The Tunisian news site Tunisia Live posted this video of the militia rolling into the airport:

With military-grade weapons widely available in Libya following last year's civil war, standoffs like Monday's show how volatile the security situation there is as the country gets ready for its first nationwide elections, currently scheduled for June 19.