A fighter jet from General Khalifa Haftar's east Libyan militia has been shot down during a bombing raid on Derna.
The MiG-21 was downed by a missile during an air raid on the east Libyan city, held by an Islamist militia coalition known as the Majlis Shura Mujahideen Derna.
Haftar's self-styled Libyan National Army has been fighting a long and brutal campaign against Islamist militias in eastern Libya, as well against the UN-recognised government in Tripoli.
"A MiG-21 fighter was shot down by a missile after the aircraft carried out an airstrike targeting militants," LNA Spokesman Naser Hassi told Reuters news agency.
Besieged Derna has been the occasional target of Haftar airstrikes, along with other bombing raids by the Egyptian airforce who back the former Muammar Gaddafi loyalist.
Islamist militias and former anti-Gaddafi rebel groups formed a militia known as the Majlis Shura Mujahideen and occupy Derna which lies around 200 miles east of Benghazi.
Egyptian fighter planes launched air strikes on Derna in May following an attack on Christian pilgrims in Egypt, claiming the militants who carried out the massacre were Libyan.
In addition to UAE and Egyptian military support, Haftar is also said to be receiving Israeli aid.