Iraqi forces said they faced tough resistance from Islamic State fighters driven out of the city of Tal Afar to a small town where they had “nothing to lose” by fighting to the end.

An advance by the Iraqi army and Shi'ite paramilitary groups into al-'Ayadiya was being slowed by snipers, booby-traps and roadside bombs, military officials told Reuters.

“The offensive started from two fronts in a bid to distract Daesh fighters,” army Lieutenant Colonel Salah Kareem said, using the Arabic acronym for Islamic State.

“A total of four suicide bombers driving vehicles rigged with explosives attacked our troops under sniper cover. We had to slow down to avoid high casualty rates among our soldiers.”

Iraqi forces have in recent days recaptured almost all of the northwestern city of Tal Afar, long a stronghold of Islamic State. They have been waiting to take al-Ayadiya, 11 km (7 miles) northwest of the city, before declaring complete victory.

“Our intelligence shows that the most diehard Daesh fighters fled Tal Afar to al-'Ayadiya,” Kareem said.

He said continuous air strikes and round-the-clock drone surveillance had prevented them fleeing to neighbouring Syria.

“They have nothing to lose ... they will fight to the last breath, Kareem said.

Islamic State mortar rounds and sniper fire struck close to the advancing forces. The army hit back with tanks, heavy machineguns and mortars.

Up to 2,000 battle-hardened militants were believed to be defending Tal Afar against around 50,000 government troops last week. It was unclear how many were left in al-'Ayadiya.

Many motorcycles carrying the Islamic State insignia had been abandoned at the side of the road outside al-'Ayadiya.

CALIPHATE IN RUINS

If the fight for the town is proving surprisingly tough, the bigger battle for Tal Afar was easier than expected for Iraqi forces.

The city's dramatic and rapid collapse after just eight days of fighting lent support to Iraqi military reports that the militants lack sturdy command and control structures west of Mosul.

Civilians who fled Tal Afar in recent weeks told Reuters of harrowing conditions in the city, where people had been surviving on bread and dirty water for months. Some militants had looked “exhausted” and “depleted", residents said.

Tens of thousands of people are believed to have fled in the weeks before the battle started. A Reuters team saw no sign of civilians in the neighbourhoods it toured on Saturday and Sunday.

Tal Afar became the next target of the U.S.-backed war on the jihadist group following the recapture in July of Mosul, where it had declared its “caliphate” over parts of Iraq and Syria in 2014.

Mosuls collapse effectively marked the end of the caliphate, but the group remains in control of territory on both sides of the Syrian-Iraqi border