Fayez Serraj sailed in from neighboring Tunisia to set up a temporary seat of power in a naval base.

The head of a UN-brokered Libyan unity government arrived in the capital by sea Wednesday to set up a temporary seat of power in a naval base despite threats from competing factions, which prevented him from arriving by air.

Western nations view the unity government as the best hope for ending Libya’s chaos and uniting all factions against an increasingly powerful ISIS affiliate, which has seized the central city of Sirte. But factions within two other rival Libyan governments, one of which is based in Tripoli, are opposed to the UN-backed body.

Fayez Serraj sailed in from neighboring Tunisia aboard a Libyan vessel, according to the unity government’s website, which denied reports that the officials had been brought in aboard an Italian ship. His arrival sparked fears of renewed clashes in Tripoli, which is controlled by several militias with different loyalties.

Hours after he landed, shops and restaurants closed, and cars lined up outside petrol stations. Opposing militias set up checkpoints in downtown Tripoli, stopping cars and searching drivers.

Late on Wednesday, witnesses said armed men attacked the offices of al-Nabaa TV network and took it off the air. The network has been giving air time to Islamists supportive of the Tripoli government.

Serraj arrived with six deputies who are members of the Presidential Council, which was established based on a UN-mediated deal signed by breakaway groups from the two governments last year. The council formed the new unity government headed by Serraj.

The officials were prevented from flying into Tripoli by a rival Islamist-backed government based in the capital. A third government is based in the east of the vast oil-rich country. Libya has been dominated by an array of militias since the 2011 uprising that toppled and killed longtime dictator Muammar Qaddafi.

“It is time for all of us as Libyans to work together for the sake of Libya,” Serraj said upon his arrival, according to the government’s Facebook page. He urged rivals to “turn the page of the past,” saying “revenge, alienation, antipathy, and hatred don’t build a state.” In a nod to Islamist factions, Serraj stressed that all laws will be compliant with Shariah.

He also vowed to unify state institutions and implement “rapid measures” to lessen the suffering of civilians. Pictures on the website showed him shaking hands with naval officers, who presented him with a golden plate.

US Secretary of State John Kerry welcomed the council’s arrival.

“Now is not the time for obstructionists to hold back progress, but rather for all Libyans throughout the country to embrace this historic opportunity for a peaceful and more prosperous Libya,” he said in a statement.

The UN envoy to Libya, Martin Kobler, praised Serraj’s “exceptional personal courage” and urged officials to facilitate an “immediate orderly and peaceful handover of power.” He tweeted: “All security actors in #Libya have responsibility to ensure safety and security of Presidency Council & #GNA.”

But Ali Abu Zakouk, the foreign minister of the Islamist-backed government, said Serraj’s presence is “unacceptable.” Last week, the Tripoli government declared a state of emergency and ordered its forces to “increase security patrols and checkpoints.” Days later, the government closed Tripoli’s air space.

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