The UN envoy to Libya, Ghassan Salame, said that retired Field Marshal Khalifa Haftar demanded guarantees for a possible withdrawal from the vicinity of the capital Tripoli.
This came in an interview with the French newspaper Libération, published on Monday.
Salame stated that "weeks ago, the parties' positions became more realistic and the issue is not only geographical any longer, as Haftar demanded guarantees for a possible withdrawal from the vicinity of Tripoli."
Salame explained that "Haftar wants guarantees from the ruling parties in Tripoli, and requests making some appointments in important state posts in his favour."
Salame added: "In return, parties are willing to negotiate with Haftar on the condition of the withdrawal of his forces."
He continued: "However, other parties do not want to negotiate with Haftar, as they consider that the retired Field Marshall lost legitimacy to be an active doer in Libya when the conflict ends."
Since 4 April, Haftar's forces have staged a faltering offensive to take over Tripoli, the location of the headquarters of the internationally recognised Government of National Accord (GNA).
The attack on Tripoli led to the death of more than 1000 people and the displacement of more than 100000 civilians, according to the GNA.
Since 2011, Libya has been witnessing a struggle for legitimacy and power, currently concentrated between the GNA and Haftar.