A heavily armed militia has taken over Libya's main airport in the capital, Tripoli, demanding the release of a leader who went missing on Sunday.
Militiamen from the al-Awfia brigade entered the airport with tanks and armoured vehicles and occupied the runway, forcing flights to be diverted.
It is unclear if the group's commander has been kidnapped or is being held for questioning by the government.
The group is refusing to leave until its demands are met.
The BBC's Rana Jawad, who was on the tarmac at Tripoli airport, said that at least two dozen armed militiamen are at the scene.
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.
She adds adds that the situation is chaotic, although not overtly dangerous at the moment, with reports that the brigade are in negotiations with security officials.
Several trucks carrying Libyan National Army personnel had arrived at the scene, according to our correspondent.
"They are on the runway, in the car park, everywhere," an official told Reuters news agency.
A representative from the brigade's hometown of Tarhouna in western Libya is at the airport to negotiate with the rebels and convince them to give up their action.
Airport sources told the BBC that at least three airlines have cancelled their flights.
Several international airlines have resumed flights to Libya, since the end of the conflict which toppled Muammar Gaddafi.
Libya's interim government took control of the airport in Tripoli this April, taking over from militia fighters who had been providing security in the absence of an official force.