East Libya-based forces carried out air strikes on port city Misrata targeting Turkish armoured vehicles and a munitions depot.
The strikes came hours after an air strike on a biscuit factory in Tripoli, 190 km west the UN envoy to Libya said could constitute a war crime.
The strikes mark a new escalation in conflict around Tripoli, where forces loyal to east Libya-based commander Khalifa Haftar have been on the offensive since early April.
The attempt by Haftar’s Libyan National Army (LNA) to take Tripoli stalled with both sides using drones and fighter jets for air strikes amid sporadic ground fighting.
Forces from Misrata led the defence of Tripoli, home to Libya’s internationally recognised government. Misrata is the second largest city in western Libya and a major source of opposition to Haftar.
Residents said the strikes were unusually powerful and followed by repeated explosions. Pictures on social media showed a large ball of fire over houses.
Libya is divided between rival political and military camps in Tripoli and the east since 2014. In recent months the conflict has become increasingly internationalised.
Haftar has backing from the United Arab Emirates, Egypt and Russia. The Tripoli government is backed by Turkey.
The LNA said its strike in Misrata targeted vehicles delivered from Turkey that arrived in Misrata port on Monday, as well as weapons and munitions.
Turkey’s foreign ministry had no information on the matter. Foreign Minister Mevlut Cavusoglu told parliament Turkey supported international efforts to bring peace to Libya.
“We see the establishment of a lasting ceasefire in Libya and continuation of efforts for a political resolution under UN auspices as a topic of priority,” he said.
East Libyan officials warned of escalation after saying Misrata seized a Libyan Airlines passenger jet operating from Benghazi.
Misrata is home to the only functioning civilian airport in western Libya. Tripoli’s Mitiga airport was shut following air strikes and shelling.
The strike on the biscuit factory in Tripoli was part of an escalating air campaign and killed at least 10 workers and wounded 35, UN Libya envoy Ghassan Salame told the Security Council in New York.
Two killed were Libyan and the rest appeared to be migrant workers, according to local emergency services.
An official at Bangladesh’s embassy in Tripoli said one of its nationals was killed and 15 wounded and hundreds of workers were in the factory when it was hit.