Eastern Libyan troops have advanced into the southern outskirts of the capital Tripoli in a dangerous thrust against the internationally recognized government.
The advance comes despite last minute efforts by the United Nations (U.N.) to quell hostilities in the northern African nation.
Fighting is going on near the former international airport, which the Libyan National Army (LNA) force, led by Khalifa Haftar, controlled by Friday night.
The move by the LNA, which is allied to a parallel administration based in the east, escalated a power struggle that has splintered the nation since the overthrow of Muammar Gaddafi in 2011.
It came as U.N. Secretary-General Antonio Guterres departed after meeting Haftar to try to avert civil war.
“I leave Libya with a heavy heart and deeply concerned. I still hope it is possible to avoid a bloody confrontation in and around Tripoli,” he said on Twitter.
Haftar had on Thursday ordered his forces to advance on the capital Tripoli, where the internationally recognized government is based.
Haftar, 75, who casts himself as an opponent of Islamist extremism but is viewed by opponents as a new Gaddafi, was quoted by Al-Arabiya TV as telling Guterres the operation would continue until terrorism was defeated.
The U.N. Security Council was briefed behind closed doors on the latest developments on Friday and expressed deep concern in a statement read after the meeting by German U.N. Ambassador Christoph Heusgen, president of the council for April.