As pro-government troops close in on the last Islamic State (Isis) fighters in the coastal Libyan city of Sirte, the few that remain have started goading their enemies to kill them and are intent on dying as martyrs.

Sources on the ground in Sirte, speaking on condition of anonymity, told IBTimes UK that few IS fighters were ever captured in the city which has been held by the militant group for over a year.

There were believed to be thousands of Islamic State fighters in Sirte, the hometown of former Libyan dictator Muammar Gaddafi, most of them foreign fighters from Tunisia and sub-Saharan Africa.

However – Libyan troops, fighting under the auspices of the UN-backed Government of National accord and drawn mostly from the city of Misrata – have made a grinding advance against the militant group with the aid of US air strikes. The troops now appear on the verge of liberating Sirte.

"Misrata troops are making progress on a daily basis. It is after two or three days they recapture a neighbourhood. Most of the city is now under their control. IS fighters are still in the city centre and the city is completely surrounded by Misrata troops," the activist explained.

Military commanders from Misrata, one of the strongest military forces to emerge from Libya's civil war following the country's 2011 revolution, believe the Islamic State leadership in Sirte has fled the city, taking refuge in country's expansive deserts to the south. Those extremists who remain expect to die in Sirte.

"The ones who are left have that strong ideology to be killed for the sake of God," the activist said. "IS fighters blackmail the fighters when they are injured or captured. They start to use strong words to blackmail the fighters till they kill them." he added.

Typically the Isis militants will shout at the Misrata fighters that they are apostates and unbelievers and do not give up fighting once they are injured. The activist said the Isis fighters often wear suicide belts on to the battlefield and will detonate their devices once the fight is lost.

"They blow themselves up with explosive belts so they kill a higher number of Misrata fighters," he said.

Misratan troops have paid a high cost to take back Sirte. The activist estimated roughly 400 had been killed in the campaign which began in May; he said as many as 2,000 had been wounded in the fighting. In one day of fighting (28 August) Reuters reported that 34 fighters were killed and 180 wounded as Libyan troops closed in on the final Isis strongholds.

As IS is pushed out from Sirte fears are being raised that the extremist group will resort to the same tactics it has used in Iraq and Syria as hold over territory is diminished. It is believed the militant group will increasingly target so-called "soft targets" attacking civilians and security forces with suicide bombers.

More than 60 were killed in Libya in a car bomb attack in the western city of Zliten in January when IS militants detonated a dump truck filled with explosives at a police academy graduation ceremony. The country had not experienced a suicide bomb attack until 2014.

In January 2015, IS fighters killed five foreign guests at Tripoli's Corinthia Hotel. A car bomb was detonated in the hotel's car park before five gunmen stormed the building.

Libyan analyst and academic Hafed al-Ghwell told IBTimes UK he expected to the militant group to cause carnage as the UN-backed government of national accord struggled to impose order within Tripoli, let alone outside of the capital.

"There will be more fragmentation, deeper divisions and a repeat of Iraq as Isis melts into the population and starts bombings and killings across the country, not just in Sirte," he said.