An airstrike on a detention centre for illegal migrants in a suburb of Tripoli killed 40 and wounded 80, a health official told Alwasat.
The airstrike was reported at the Tajoura center for illegal immigration, just east of Tripoli, in a hangar that had an estimated 120 migrants at the time.
"Nearly 40 bodies were recovered from the bombardment and more bodies are being pulled out of the rubble," said Malik Merset, a spokesman from the emergency services.
The presidential council of the Al-Wefaq government, led by Fayyez al Saraj, condemned the air strike and called on the UN Mission in Libya to send a fact-finding mission to inspect the site.
The Libyan National Army, led by Khalifa Haftar, denied it had targetted the detention center, saying militias shelled it after an airstrike by the LNA on a camp.