“Sirte has been totally liberated,” Ahmad al-Mesmari announced on television.

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“The operation was quick and lasted only three hours,” Mesmari said, although preparations had started months earlier with air strikes on positions of pro-GNA forces.

He said Hifter loyalists struck from five land and sea positions and had air cover. He did not give further details.

The GNA did not immediately confirm the fall of Sirte, but a pro-GNA military commander in the city, speaking on condition of anonymity, acknowledged the loss.

The oil-rich North African country has been plunged into chaos since the 2011 Nato-backed uprising that killed long-time dictator Muammar Gaddafi.

It is now divided between the GNA based in the capital Tripoli and Hifter’s forces in the east and which also control most of the country’s south.

Tensions escalated last year when Hifter launched an operation in January to “purge” southern Libya “of terrorist groups and criminals” and seized several towns with support from local tribes.

Hifter then set his eyes on Tripoli, launching an offensive on the capital in April to unseat the GNA.

The GNA has sought help from Turkey, whose parliament passed a bill allowing the government to send troops to Libya to shore up the Tripoli government.

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On Sunday, Turkey’s President Recep Tayyip Erdogan announced that his soldiers had begun deploying in Libya.

Although there has been no immediate confirmation from Tripoli of that deployment, Turkey’s involvement has raised concern among Libya’s neighbours and in Europe.

Egypt said it will hold a meeting Wednesday with the foreign ministers of France, Italy, Greece and Cyprus for talks on “ways to push efforts to reach a comprehensive settlement” in Libya.

Algeria, which on Monday hosted GNA prime minister Fayez al-Sarraj as well as Turkish Foreign Minister Mevlut Cavusoglu, urged the UN Security Council to impose a ceasefire in Libya.

The European Union, for its part, expressed concern over an “imminent” escalation of violence around Tripoli.

While the GNA is backed by Turkey and Qatar, Hifter has the support of Egypt, the United Arab Emirates and Russia.

On Friday, Hifter urged all Libyans to take up arms in response to any Turkish involvement in his country.

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Sirte was at one stage a bastion of Islamic State (Isis) which moved into Libya amid the chaos that followed Gaddafi’s ouster.

Isis controlled Sirte from early 2015 until the GNA, backed by US air strikes, evicted the jihadists in a seven-month battle that cost hundreds of lives.

Hifter says he is seeking to rid Tripoli of armed groups and combat extremism. His opponents say he has fuelled war and instability, and fear he will return Libya to one-man rule.

Hifter’s LNA earlier Monday said on social media they were “steadily advancing towards the heart of Sirte” after seizing control of Ghardabiya airport on the outskirts.

It said forces at the airport surrendered with their equipment and reported clashes in several parts of Sirte.

Pro-GNA forces said in a Facebook post they had come under attack in Sirte and that mercenaries from Chad were fighting alongside the LNA.

Additional reporting by Reuters and Bloomberg