The dispute over mercenaries and foreign fighters has long been an obstacle, particularly ahead of Libya's landmark general elections due in December.

Libya has been engulfed in chaos since a NATO-backed uprising toppled longtime dictator Moammar Gadhafi in 2011. The oil-rich country was for years split between rival governments, one based in the capital of Tripoli and the other in the eastern part of the country. Each side is backed by different foreign powers and militia groups.

The UN mission mediating between the rivals said a 10-member joint military commission, with five representatives from each side, signed a ``gradual and balanced'' withdrawal deal Friday, at the end of three days of talks facilitated by the UN in Geneva.

The plan would be ``the cornerstone for the gradual, balanced, and sequenced process of withdrawal'' of the mercenaries and foreign forces, the mission said.

Jan Kubis, the UN special envoy for Libya, welcomed the move as ``another breakthrough achievement.''

Libya's split came into the forefront in 2019, when self-styled military commander Khalifa Hifter, allied with the east-based administration, launched an offensive to take Tripoli from armed militias loosely allied with the UN-supported but weak government in the country's capital.

Hifter was backed by Egypt, the United Arab Emirates, Russia and France. But, his 14-month campaign and march on Tripoli ultimately failed in June 2020, after Turkey sent troops to help the UN-supported administration, which also had the backing of Qatar and Italy.

After the fighting largely stalemated, subsequent UN-sponsored peace talks brought about a cease-fire last October and installed an interim government that is expected to lead the country into the December elections. The cease-fire deal also included the departure of foreign forces and mercenaries within three months something that was never implemented.

Friday's deal ``creates a positive momentum that should be built upon to move forward towards a stable and democratic stage, including through the holding of free, credible and transparent national elections on 24 December, with results accepted by all,'' Kubis said.

The sides said they would now go back discuss this with their base and concerned international parties ``to support the implementation of this plan and the respect of Libya's sovereignty.''

The deal also called for the deployment of UN observers to monitor the cease-fire before the implementation of the withdrawal plan.

In December, then UN acting envoy for Libya Stephanie Williams estimated that there have been at least 20,000 foreign fighters and mercenaries in Libya over the past few years, including Russians, Syrians, Sudanese, and Chadians.

Though the agreement on mercenaries is seen as a step forward, earlier this month, Libyan lawmakers in the east dealt a setback to the peace process by voting to reschedule the parliamentary elections for January, a month later.

It wasn't immediately clear how the lawmakers' move would translate into a postponement of the vote.