Smoke, rockets and fear on frontline of the battle for Mosul

The gunfire stopped, and the Kurdish peshmerga commander confidently declared the village of Shakouli liberated from Isis. Pleased to have made such good progress in just a few hours, Lieutenant Mehsen Gardi started congratulating his officers.

But he was interrupted by a large explosion that caused the ground to tremble. It was a suicide bomb, followed in quick succession by a second and then third.

Gardi had underestimated his opponent. As Isis (Islamic State) battles to defend Mosul, its last major stronghold in Iraq, its footsoldiers are putting up a fierce fight to stop the troops reaching the city.

More than 4000 Kurdish peshmerga fighters, supported by dozens of US, French and British special forces advisers on the ground and coalition planes in the skies, began moving in on villages and towns surrounding the city from the east. The Iraqi Army is approaching from Baghdad to the south.

"There were less than 10 Daesh in the village," said Gardi. "But they were running around like rats in and out of tunnels and surprising us with suicide attacks and snipers."

Isis fighters burnt tyres in an attempt to obscure the peshmerga's view of the approach to the city. From their position on top of a hill some 32km from Mosul, on the eastern Khazir frontline, peshmerga troops could see the plumes of black smoke rise and hear the sound of crackling gunfire. The soldiers responded with katyusha rockets, which whistled overhead as they left the launcher.

There were about 15 US special forces watching the battle and calling out coordinates for the rocket attacks.

It is the country's biggest operation since the 2003 invasion. It also marks the third time in 13 years the US and its allies have tried to "liberate" Mosul: in 2003 from Saddam Hussein, a year later from Sunni insurgents and now from Isis. Mosul fell to the Islamist group in June 2014, when its jihadists blitzed across northern and western Iraq.

By nightfall local time the peshmerga had retaken three villages, but it cost them eight men. Despite the setbacks Gardi was confident they could reach the outskirts of the city before the end of the week, when they will hand over to the Iraqi Army.

American F16s flew low over Mosul, while Iraqi Army mortars pummelled the southern outskirts.

Worried there will effectively be a siege once troops move in, trapped residents have been stockpiling supplies to last several weeks. "We set up a fortified room in the house by putting sandbags to block the only window and we removed everything dangerous or flammable," one resident, who gave his name as Abu Maher, said. "I spent almost all my money on buying food, baby milk and anything we might need."

Isis is using the more than a million residents as human shields, threatening to execute anyone who tries to leave. The estimated 8000 jihadists live among the civilians.