The Libyan authorities took back control of the Tripoli international airport on Monday after ex-rebels occupied the runway, surrounding planes and grounding all flights.

The authorities have complete control over the airport,” deputy interior minister Omar al-Khadrawi told journalists in the capital, adding that dozens assailants were arrested, Al Jazeera reported.

He also said that an investigation had been launched to determine the circumstances of Habshi’s disappearance.

The group of ex-rebels called al-Awfea Brigade, from the town of Tarhouna, 80km southeast of the Libyan capital, was demanding the release of their leader whom they said was being held by Tripoli’s security forces, government official said.

Security forces flooded the airport after negotiations broke down, he said.

Tripoli’s security commission, which answers to the interior ministry, said it was not involved with “the disappearance and abduction” and that it has launched an investigation to find out the reason for his disappearance, AFP reported.

The NTC is still struggling to fully integrate many former rebels who fought forces loyal to Muammar Gaddaf and still won’t let their arms down.

The ex-rebels have remained in organised armed brigades, taking it upon themselves to ensure law and order in the absence of fully functional police and armed forces, Al Arabiya reported.

Monday’s assault on Tripoli airport came as Libya prepares to hold elections for a 200-seat constituent assembly by June 19, as pledged by the NTC although an official has told Al Jazeera that the ballot would be delayed until the first week of July at the earliest.