The aircraft belonged to the forces of commander Khalifa Haftar, who controls the east of Libya and much of the country's south.

Haftar's self-styled Libyan National Army launched an offensive in April to try to seize Tripoli from the UN-recognised Government of National Accord (GNA).

The jet made an emergency landing after it "suffered a technical problem", according to a statement from a parallel administration based in eastern Libya, backed by Haftar.

An AFP photographer at the scene on Monday had said the plane was transporting two bombs.

The defence ministry said the jet has since been taken from its landing site near Medenine city, some 100 kilometres (60 miles) from the Libyan border, to a Tunisian storage facility.

The warplane's pilot, a colonel who was the sole person on board according to the ministry, is being questioned by Tunisian security forces.

The GNA foreign ministry said Monday on Facebook that a "liaison commission" had been set up by its embassy in Tunis to discuss the fate of the plane.

The rival administration in eastern Libya has meanwhile said it is in contact with Tunis to ensure the safe return of the aircraft and its pilot.

"The question of which entity this plane should be returned to will be at the centre of the question of restitution", said Haykel Ben Mahfoudh, an expert on international law.

"Tunisia, if it has maintained a neutral position toward the conflict in Libya, is particularly keen to respect the status of the GNA recognised by international institutions", he added.

More than 1,000 people have been killed since Haftar launched his offensive on Tripoli, according to the World Health Organization, while more than 100,000 people have been displaced by the violence.