SKHIRAT, Morocco (Reuters) - Libya's warring factions began a round of U.N.-backed negotiations on Thursday in an attempt to end their conflict, with the U.N. envoy telling factions they must reach a final deal by Sept. 20.
Western powers are pressing for the U.N.-sponsored deal to form a unity government between the two rival factions whose conflict is pushing the North Africa state deeper into chaos four years after rebels ousted Muammar Gaddafi.
An internationally recognized government and elected parliament has operated out of the east of the country since last year when an armed faction called Libya Dawn took over Tripoli and set up its own self-declared government.
"We are very hopeful that they (the parties) will understand that the deadline of Sept. 20 must be the last one, must be the one that will allow Libya to get out of the crisis," U.N. envoy Bernardino Leon told reporters in Skhirat in Morocco.
Leon did not say what would happen if his Sept. 20 deadline was not met. The target date for an agreement has been repeatedly pushed back. The mandate of the House of Representatives, seat of Libya's internationally recognized government, expires in October, adding pressure for a deal.
Delegates from the international recognized government have already accepted a preliminary deal, but the Tripoli faction has yet to agree.
Negotiators from both sides are under pressure from hardliners who see they can still gain from continued conflict. Military forces on both sides are loose alliances of former anti-Gaddafi rebels who turned against each other or whose loyalties are more to tribal or regional allegiances.
But Libya's turmoil is an increasing concern for European leaders as Islamic State militants gain ground there and smugglers take advantage of the chaos to ship thousands of illegal migrants across the Mediterranean Sea to Europe.
(Reporting by Aziz El Yaakoubi; writing by Patrick Markey)