CAIRO (Reuters) - The head of Libya’s U.N.-backed government will hold talks in Paris this week with a powerful military commander who has so far rejected his authority, a diplomatic source said.

FILE PHOTO: General Khalifa Haftar, commander in the Libyan National Army (LNA), leaves after a meeting with Russian Foreign Minister Sergei Lavrov in Moscow, Russia, November 29, 2016. REUTERS/Maxim Shemetov/File Photo

The talks between Prime Minister Fayez al-Serraj and commander Khalifa Haftar are aimed at stabilizing the oil-producing country, which has been mired in chaos and fighting since rebels toppled strongman Muammar Gaddafi in 2011.

Western governments are pushing the U.N.-backed political agreement that installed Serraj’s Government of National Unity, but Haftar, whose forces have gained ground in the east of the country, has refused to accept the government’s legitimacy.

The two rivals held talks in Abu Dhabi in May, the first in more than a year and a half.

“I know Haftar is in Paris already, Serraj is due to arrive soon. They are aiming for Tuesday,” the diplomatic source told Reuters.

A French government spokesman had no comment, and officials with Serraj’s government did not return calls. But Libya’s Nabaa TV cited a Libyan government source saying Serraj would arrive in Paris on Tuesday.

Years of turmoil in Libya have allowed Islamist State militants and people-traffickers to thrive: the North African country is the main point of embarcation for migrants attempting the dangerous voyage across the Mediterranean to Europe.

With no national army, brigades of former rebels who once fought together to oust Gaddafi have become powerful competing factions. Each is backed by rival political leaders in fluid alliances locked in a struggle for control.

Serraj is loosely supported by a coalition of armed brigades in the west of the country, but even in the capital Tripoli his government has struggled to impose its authority.

Diplomats say the Paris talks will focus on agreeing on key principles - that the political accord is the way forward, that no military solution exists, and Libya’s military should be under civilian control.

French President Emmanuel Macron wants France to play a more active role in tackling the Libyan crisis. He plans to meet Haftar and Serraj, the source said, adding an encounter could help bring around the commander by offering him “some form of legitimacy”.

The idea would be to bring them into an agreement allowing the U.N. to implement the peace deal and set up elections.

Libya’s neighbors and regional powers have often disagreed on how to resolve the crisis. Egypt and the United Arab Emirates are closer to Haftar and his self-styled campaign against Isamist militants. Worried about security, Algeria and Tunisia push a more inclusive approach.

Even in the European Union, splits have emerged over how best to bring Haftar into the fold. French officials fear Islamic State militants - who were driven from Libya’s coastal city of Sirte last year - and other jihadists could try to exploit the country’s power vacuum to regroup there again after losing substantial ground in Syria and Iraq.