Tripoli airport was closed yesterday after a bomb exploded on the runway.

Supposedly one of the best guarded places in Libya, unknown people managed to get on to the runway, plant an explosive device at dawn and detonate it using a timer, Transport Minister Abdelqader Mohammed Ahmed said.

“There was a small explosion,' Ahmed said. “When security and the airport protection force arrived they found a timer.”

The morning incident forced airlines to divert flights and cancel others bound for the Libyan capital.

Air Malta cancelled its 5pm flight and a spokesman said the airline was told the airport had closed for “operational reasons”.

Sources said about 100 passengers had been booked on the outgoing flight with 80 on the return evening service. Passengers on an Emirates flight bound for Tripoli, via Malta, disembarked at Malta International Airport because of the closure.

Officials had first suspected rockets fired by militias had landed on the runway as gunfire could be heard in the capital during the night.

Rival militias often fight over territory or influence in Tripoli or the rest of the country.

Authorities reopened the airport by using first an alternative runway.

Mainly Libyan airlines restarted operations in the afternoon.

Ahmed said authorities would improve airport security but analysts say the nascent police and army, still in training, are no match for battle-hardened militias seizing at will oil fields or ministries to grab power and oil revenues. Libya’s government is still struggling to assert its authority three years after dictator Muammar Gaddafi was ousted.

Militias that helped overthrow Gaddafi have kept their guns in order to demand power, oil wealth and influence.

Flight had to return twice

An Air Malta flight was forced to return to Malta twice yesterday because of technical issues.

Flight KM624 on the Malta-Milan Linate route that departed as scheduled at 7.55am had to return to Malta twice because of “technical reasons”, Air Malta said in a statement.

After being serviced by the airline’s engineers, the aircraft departed again but returned as a precautionary measure since the technical issue was reported again. On both occasions, the aircraft landed normally in Malta and at no point was the safety of the passengers compromised.

The aircraft was inspected by engineers, but the incident affected a number of flights.

Customers were urged to contact Air Malta or the airport for updates.

A spokesman said the airline gave utmost importance to the safety and well-being of its clients and crew and apologised for any inconvenience caused by circumstances beyond its control.