A militia fighting on behalf of Libya’s UN-backed government has warned that Isis militants are regrouping in order to launch a new attack on the city of Misrata, the country’s trade capital.

“We have spotted movements by Daesh in the south of Sirte, where they are trying to regroup and break through our forces’ lines in the south,” Mohamed Ghasri, spokesperson and senior commander of the Misrata-based al-Bunyan al-Marsous forces, said on Wednesday.

The militia was a key force in helping drive Isis out of the coastal city of Sirte last year after a gruelling six-month-long campaign aided by US air strikes.

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Al-Bunyan al-Marsous now believes an attack on the port city is imminent as Mr Ghasri warned that his troops have lacked international support to fend off Isis since driving them from Sirte city in 2015.

Isis’s leaders in the country are now operating in the southern Sirte countryside. Mr Ghasri did not give details on how many fighters Isis is believed to be readying for a fresh assault on Misrata.

The civil war that has engulfed Libya since the overthrow of Muammar Gaddafi in 2011 has allowed warlords and extremists to gain footholds across the country.

In pictures: Isis' Libyan stronghold of Sirte Show all 10 1 /10 In pictures: Isis' Libyan stronghold of Sirte In pictures: Isis' Libyan stronghold of Sirte Isis in Sirte Isis fighters parade through in Sirte in 2015 In pictures: Isis' Libyan stronghold of Sirte Isis in Sirte Islamic State (IS) group jihadists on the outskirts of Libya's western city of Sirte AFP/Getty In pictures: Isis' Libyan stronghold of Sirte Isis in Sirte A photo of a billboard in Sirte, Libya, listing seven rules for women's clothing, saying they must be loose-fitting and undecorated HRW/social media In pictures: Isis' Libyan stronghold of Sirte Isis in Sirte Isis militants process down a street in the coastal city of Sirte in Libya this week; the group has heralded Libya as its ‘strategic gateway’ to attack Europe AFP/Getty Images In pictures: Isis' Libyan stronghold of Sirte Isis in Sirte An Isis lecture on Sharia at the Ouagadougou complex in Sirte, Libya, in 2016. HRW/social media In pictures: Isis' Libyan stronghold of Sirte Isis in Sirte A sign reading "The city of Sirte, under the shadow of Sharia" as smoke rises in the background while forces aligned with Libya's new unity government advance on the eastern and southern outskirts of the Islamic State stronghold of Sirte on 9 June. Reuters In pictures: Isis' Libyan stronghold of Sirte Isis in Sirte Fighters loyal to Libya's GNA prepare to launch attacks against Isis as they continue their resistance on the outskirts of the western city of Sirte Getty In pictures: Isis' Libyan stronghold of Sirte Isis in Sirte Forces loyal to Libya's UN-backed unity government are seen during clashes with jihadists of the Islamic State (IS) on the western outskirts of Sirte on June 2, 2016. AFP/Getty Images In pictures: Isis' Libyan stronghold of Sirte Isis in Sirte Forces loyal to Libya's UN-backed unity government fire during clashes with Isis around 14 miles west of Sirte on June 2, 2016. AFP/Getty Images In pictures: Isis' Libyan stronghold of Sirte Isis in Libya

A new round of diplomacy between the internationally recognised government of Prime Minister Fayez al-Serraj and rival eastern commander Khalifa Haftar began on Tuesday. A ceasefire has been implemented – except in the fight against terrorist organisations – and elections are possibly on the table in talks in Paris by the French government.

Faced with a string of military defeats in its “caliphate” across Syria and Iraq, observers believe Isis will concentrate on its operations in countries such as Libya, which face power vacuums, and step up terror attacks on civilians worldwide.