Forces loyal to Libya's internationally recognised government said that on Wednesday they had shot down a war plane belonging to a rival administration controlling Tripoli.
Both governments have been fighting each other with aircraft and ground troops on several front, part of a wider conflict in the oil-producing nation four years after the ousting of Muammar Gaddafi.
"Our forces shot down a plane trying to attack Zintan airport," said Mohamed El Hejazi, a spokesman for the army loyal to the official government, which has been based in the east since a rival faction seized Tripoli in August.
Omar Matoog, a spokesman for the airport in Zintan, a western region allied to the eastern government, also said a MiG belonging to a rival administration in Tripoli had been shot down.