Libyan prime minister-designate under a proposed National Unity government Fayez Seraj attends a news conference.

Ten Libyan cities which were under control of the non-recognized government of Tripoli have broken away and pledged their support to the UN-backed government, one of the municipalities announced online Thursday.

The news is a major blow to the unrecognized authority in Tripoli that is refusing to give up power.

The announcement came in a statement on the official Facebook page of the Sabratha municipality, 70 kilometers west of Tripoli, after a meeting for the heads and representatives of the 10 coastal cities in the west of Libya, located between Tripoli and the border with Tunisia.

The UN Security Council unanimously welcomed the Libyan unity government’s move and said it was time to cut off ties with rival administrations.

The statement came after prime minister-designate Fayez al-Sarraj made his first public appearance in the Libyan capital, two days after his arrival angered the Tripoli-based government.

The council said Sarraj’s arrival in Tripoli “was an important step towards bringing stability to the country and bringing the political process back on track.”

Council members renewed their appeal to world governments “to cease support to and official contact with parallel institutions that claim to be the legitimate authority but are outside of the Libyan political agreement.”

Sarraj was picked by the United Nations in October to lead the new unity government, but faced much resistance from Libya’s myriad political factions and armed groups.

Libya has had two rival administrations since mid-2014 when a militia alliance overran the capital, setting up its own authority and forcing the internationally recognized parliament to flee to the country’s east.

After his arrival by sea on Wednesday, the Tripoli administration demanded that Sarraj leave or surrender. The rival group had denied him permission to fly into the capital.

Sarraj and a number of his ministers turned up at a Tripoli mosque for Friday prayers after winning support from 10 western cities and guards who secure the country’s key oil terminals.

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