TUNIS: Libya's rival parties met in Tunis Thursday for talks on a disputed U.N.-brokered deal backed by the international community to set up a unity government in the war-wracked country.

The talks were to focus on efforts to move forward with the process ahead of an international summit on Libya scheduled for Sunday in Rome, the United Nations Support Mission in Libya (UNSMIL) said.

The U.N. envoy for Libya, Martin Kobler, and representatives of rival parliaments were attending the talks at a hotel in a Tunis suburb, with foreign diplomats invited as observers.

UNSMIL said the talks could carry on until late Thursday or into Friday morning.

On Tuesday, ambassadors to Libya from several EU countries and the United States warned against attempts to derail the U.N.-brokered deal, insisting it is the only way forward.

Their statement came after the rival parliaments announced a deal of their own that was reached without U.N. participation.

It urged those who still oppose the U.N. proposal to act "urgently and responsibly in the interests of the Libyan people, and to join the majority who want peace in unity under a stable and inclusive" national unity government.

The statement echoed one by Kobler on the deal announced in October by his predecessor, Bernardino Leon, after arduous negotiations, which stipulated the creation of a unity government.

That agreement "is the only available way to move the process forward and quickly," Kobler told representatives of the parliaments on Monday.

That deal was rejected by Libya's internationally recognized parliament, which is based in eastern Libya, and by the rival General National Congress in Tripoli.

On Sunday, they announced agreement on a joint "declaration of principles" aimed at resolving the crisis that has plunged Libya into chaos since a 2011 uprising.

Kobler urged the lawmakers to join the UN-brokered process in a bid to end the conflict that has endured since the revolt that toppled dictator Moamer Kadhafi.

Libya has had two administrations since August 2014, when an Islamist-backed militia alliance overran Tripoli, forcing the recognised government to take refuge in the east.