Watch: Isis militants parade 21 captive Peshmerga fighters in cagesIBTimes UK

A ground offensive by Peshmerga-led troops was launched to retake former Kurdish villages near Khazir, to the east of Mosul, from Islamic State (Isis). The military operation involved around 5,500 Peshmerga fighters including Zeravani Special Forces, a paramilitary Kurdish outfit.

In a pre-dawn raid, soldiers re-took abandoned villages in Isis-held territory which was once populated by Kurds. "I am very happy to help liberate these villages today, because they are Kurds like us," First Lt. Hemin Rashid, a Zeravani Peshmerga fighter from Halabja told media outlet Rudaw.

"Isis is seeing our forces but we cannot see them because they hide inside civilian homes and in tunnels," Zeravani spokesman Dilshad Mawlood said. Fighting appeared heavy. Trucks came back from the frontline with the wounded as mortar fire and roadside bombs hampered the advance.

Mawlood told Rudaw that, "other than taking the villages, the other goal is to push Isis threat further from the town of Khabat, and the third goal is to get closer to the final goal that is Mosul."

A joint offensive on Mosul, Iraq's second-largest city and an Isis stronghold involves coordination between Iraq's military, Kurdish forces and the international coalition.

"This is one of the many shaping operations expected to increase pressure on Isil [Isis] in and around Mosul in preparation for an eventual assault on the city," said a statement from the Kurdistan Region Security Council (KRSC) announcing the operation.

Loaders and excavators dug trenches and built dirt mounds as Kurdish forces advanced. "They are digging trenches to make sure suicide trucks don't come this way and then the main confrontation will start," explained Qadir Hama Saleh, a Peshmerga from Kirkuk.

Troops from the US-led coalition were seen close to the front line of the offensive in armoured vehicles outside the village of Hassan Shami. A Reuters report claimed they were American but this was not confirmed officially.

The ground deployment of coalition military personnel at the front line in northern Iraq has been reported, although US Army Colonel Steve Warren, the Baghdad-based spokesmen would not confirm which country they were from.

"They may be Americans, they may be Canadians or from other nationalities," he said, when told by Reuters that some forces were reported to be wearing maple leaf patches, the emblem of Canada.