An MiG-23 jet which was being flown by forces loyal to Libya’s internationally recognized government was the second to go down in the past week
The fighter jet was shot down as it carried out air strikes on opposition positions in the coastal city of Benghazi.
ISIS have claimed its fighters downed the plane, according to SITE Intelligence Group, a US monitor of jihadist activity on the Internet.
On Monday, another MiG-23 crashed near the eastern city of Derna after attacking ISIS positions.
Nasser el-Hassi, spokesman for the government’s forces, told AFP news agency the plane was shot down in Qaryunes, northwest Benghazi, as it bombed targets on Friday.
A military source said the pilot survived having parachuted to safety, but his whereabouts were not immediately clear. It was the second military air crash this week.
Brigade General Saqr al-Jaroushi, a Libyan military official, also confirmed the incident to the Associated Press.
On Monday, another MiG-23 operated by forces loyal to Libya’s recognised government crashed near the eastern city of Derna after attacking fighter positions.
The LANA news agency, which is close to the recognised government, blamed “technical problems” for the downing.
Before crashing, the fighter had carried out raids on Islamic State of Iraq and the Levant (ISIL) positions about 15km from Derna.
Two administrations are vying for power in war-ravaged Libya, one based in the capital Tripoli backed by a coalition of fighters, and the recognised government, exiled in the east.
In early January, another MiG 23 came down in Benghazi, the main city in the east.
The air force answers to the internationally recognised government in the east of the country, where its soldiers have been fighting armed groups since 2014.
Chaos has engulfed Libya since the fall of dictator Muammar Gaddafi’s regime in 2011, and has fostered the rise of ISIL, which based itself in Sirte in eastern Libya.