TRIPOLI  - A militia of Libyan ex-rebels seized the runway of Tripoli International airport on Monday, surrounding planes and grounding all flights after their leader's apparent arrest, officials said.

The "assault" was carried out by gunmen who fired into the air and slightly wounded an airport employee, causing panic among travellers, according to the official LANA news agency, which cited witnesses.
"It is total confusion. Everyone is fleeing," an official at the airport told AFP, adding that several armoured vehicles were positioned on the tarmac blocking traffic. "Cars mounted with anti-aircraft guns and armed men are surrounding the aircraft and preventing them from moving," another official said, adding that some passengers were forced to leave planes.
The motive of the gunmen was to pressure the government to explain the whereabouts of their leader, Abu Ajila al-Habshi, according to LANA.
Mohammed al-Harizi, spokesman for Libya's interim government, said earlier an investigation had been launched to determine the circumstances regarding the Al-Awfya brigade commander. Tripoli's security commission, which answers to the interior ministry, said it had nothing to do with "the disappearance and abduction of Colonel Abu Ajila al-Habshi" and that it was still tracking those responsible. The attack forced the diversion to Tripoli's Matiga military air base of some flights, including to and from Amman, Istanbul, Rome and Vienna, according to officials and flight monitoring websites.
The situation inside was calm but tense after the attack, with only a few passengers waiting the situation out and and all airline counters closed, an AFP journalist at the scene said.
Trucks mounted with heavy weapons remained parked under some airliners and gunmen shuttled in and out of the luggage hall which opens out onto the tarmac. "Members of the Al-Awfya brigade entered the plane. They were fully armed and they forced us off," Ahmed Loshta, a Tripoli resident who had been due to fly to Italy, told AFP. "Some armed people occupied the runway. There was a truck with a machinegun mounted and individuals carrying AK-47s. They want somebody to be released," added Saleh Kawas, a Syrian who had been due to leave for Jordan.
Late in the afternoon, a handful of elders in traditional tribal garb arrived on the scene. Dozens of pickup trucks mounted with anti-aircraft guns rushed in minutes after, sparking a new exodus of civilians from the airport. Intermittent gunshots were heard just before sunset but it was unclear whether it was a two-way exchange of fire or a bid by the newly arriving forces to muscle the brigade out of the airport.
A member of a Tripoli brigade said the gunfire was just a "scare tactic." Army spokesman Ali al-Sheikhi, quoted by LANA, said that "negotiators were trying to persuade the assailants to leave the airport through pacific means in order to avoid the use of force." He denounced the attack as an "assault on the state and its institutions."
The ruling National Transitional Council (NTC) is still struggling to fully integrate many Libyans who fought forces loyal to dictator Moamer Gaddafi before he was ousted and killed in October last year.
The former rebel fighters have remained in organised armed brigades. The ministries of defence and interior have integrated many of them into their ranks but some are still a law unto themselves.
The NTC took control of Tripoli airport in April from a Zintan brigade that had been guarding the facility since the capital's liberation in August 2011.
Such militias secured many strategic sites in Libya after they defeated Gaddafi loyalists backed by NATO-led air strikes during last year's Arab Spring-inspired revolution.
The NTC has called for their handover, but several other similar militias of former rebels are still guarding important buildings and facilities in the North African country.
Monday's incident at Tripoli airport comes as Libya prepares to hold elections for a 200-seat constituent assembly by June 19, as pledged by the NTC.
Flashes of violence, such as a deadly raid on government headquarters last month, have raised concerns over the capacity of authorities to secure the first election after decades under Gaddafi.
Ethnic unrest in the south, calls for greater autonomy in the east and corruption are just some of the challenges facing Libya's interim leaders.
Since the start of the Arab Spring, elections in the region have benefited Islamists, including in Egypt, Libya's neighbour to the east, and Tunisia to the west.