The UN special envoy for Libya, Jan Kubis, has resigned less than a year after taking on the role in January, diplomatic sources at the United Nations said on Tuesday.
"Kubis has resigned," a diplomat told AFP. Several other diplomatic sources confirmed the surprise development.
No official reason was given for the resignation, which comes just weeks before the Libyan elections scheduled for December 24. A successor is yet to be appointed.
Also on Tuesday, Libya's election commission announced 98 candidates who will contest the presidential election, including the son of the former dictator Muammar Qaddafi, Saif Al Islam Qaddafi, eastern military commander Khalifa Haftar and Aguila Saleh, speaker of the eastern-based parliament. Only two of the candidates are women.
More than 2.8 million Libyans have registered to vote in the UK-backed process, in which Mr Kubis played a large part.
Libya has been engulfed in chaos since a Nato-backed uprising in 2011 that toppled and killed Qaddafi. The country was for years split between rival governments – one based in the capital, Tripoli, and the other in the eastern part of the country. Each side is backed by different foreign powers and militias.
In July, Mr Kubis accused spoilers of trying to obstruct the vote to unify the divided nation. The Security Council said that any individual or group undermining the electoral process could face UN sanctions.