VIDEO: Iraqi Army Troops Take ISIS Militants’ Trenches, Tunnels in Fallujah
ISIS fighters had built the tunnels around Fallujah to defend their base in the city.
Iraqi troops are battling to retake the city, which fell to ISIS in 2014.
Aid groups estimate that 50,000 civilians remain trapped inside Fallujah.
It is the last major city in western Iraq still held by the extremist group.