The Libyan National Army says it has advanced into the outskirts of Tripoli as it continues its thrust against the internationally recognised government.
Fighting has been reported near the former international airport, which the LNA claims now to control.
The secretary general of the United Nations held talks with offensive leader Khalifa Haftar on Friday, but left the country without achieving a breakthrough.
“I’m leaving Libya with deep concern and with a heavy heart,” said Antionio Guterres. “I still hope that it would be possible to avoid bloody confrontation in and around Tripoli and the United Nation will remain available to facilitate any political solution able to unify the Libyan institutions.”
The Prime Minister of Libya Fayez al-Serra was filmed preparing the defence of the city. The LNA controls the East of Libya, running a parallel administration to that of the Tripoli government.