A line of trees 500 metres away from his position illustrated how he can't afford to be complacent.

A day earlier, a suicide bomber had rushed out of the thick green vegetation and killed five of his comrades after Kurdish forces had fought for 10 days to gain the upper hand in Fadiliya, where 1,000 people remain trapped, surrounded by roadside bombs.

Iraqi and Kurdish forces have cleared more than 30 villages like Fadiliya during their offensive to drive Islamic State from its main Iraqi stronghold of Mosul, in what is expected to be the biggest battle in Iraq for more than a decade.

Clearing the hardline Sunni militants from areas where they once imposed a reign of terror is proving to be a slow and risky mission. Securing Mosul - with a population of 1.5 million - could take months in the event of victory.

When Kurdish fighters first entered Fadiliya, they faced a barrage of suicide bombers screaming Allah hu Akbar (God is Greatest) while speeding towards them in cars, SUVs, motorcycles, and Humvees stolen from the Iraqi army.

"On the first day there were ten suicide bombers coming at us from all directions. All kinds of cars," said Yihya. "Fighting street to street. House to house. They fired at us with machine guns too."

The jihadists were mostly in their 20s, Iraqis and also what Kurdish officials describe as the most ruthless and efficient Islamic State radicals - foreign fighters from places like Chechyna.