Libyan commander Khalifa Haftar called on his forces on Saturday to rally against Turkey, which has helped his Tripoli-based rivals turn the tide of a military conflict around the capital, Reuters reports.
Recent advances by forces aligned with the internationally recognised Government of National Accord (GNA), including the seizure of a key air base, have thrown a year-long offensive on Tripoli by Haftar's Libyan National Army (LNA) into jeopardy.
They have also drawn a threat by the LNA, which is backed by the United Arab Emirates, Egypt and Russia, to carry out a massive air campaign in retaliation.
On Saturday the GNA forces pressed forward in some outlying districts of Tripoli, where they say they have had to pick their way through mines and other explosive devices laid by the LNA.
The LNA said it had withdrawn from some areas, but had also staged an ambush at Yarmouk military camp in Tripoli and killed or captured rival combatants.
Haftar, in an audio message addressed to his forces, urged them to battle the "colonial" intervention by Turkey until its defeat, in a reference to one-time Ottoman control of Libya.
"You are creating glory while fighting the odious coloniser greedy for our wealth," he said. "And you are waging war on all fronts, a war in which there is nothing but victory."
Haftar's comments were released as US President Donald Trump appealed for a rapid de-escalation of the conflict in Libya in a call with Turkish counterpart Tayyip Erdogan.
Turkish Foreign Minister Mevlut Cavusoglu said separately his country had "changed the balance" in Libya and averted a "full-blown civil war."
"The only solution in Libya is a political solution and Haftar needs to understand this," he said in a TV interview.