Peshmerga soldiers gather the night before an offensive starts to retake Mosul, near the Ba'ashiqah front line in Iraq on Oct. 19.

The Mosul campaign aims to crush the Iraqi half of the caliphate declared by ISIS in Iraq and Syria.

Photographer Harry Chun traveled across the front line near Mosul with fighters from the Kurdistan Freedom Party (PAK), a Kurdish militant group affiliated with the Peshmerga, as they engaged with ISIS.