Four months into the campaign to reclaim Mosul from the Islamic State, Iraqi troops have taken the city's eastern portion. But the fight for the western part is only just beginning. Western Mosul is the core of the Islamic State's resistance. An estimated 2,000 Islamic State fighters are still in the area, along with more than 750,000 civilians, some of whom are suspected sympathizers of the extremist group. On top of that, the dense, cramped quarters of western Mosul's Old City will present an urban warfare environment even more challenging than that of the eastern part of the city, which took three months to clear. The fight for western Mosul is a critical turning point in the operation to retake the city, and it promises to be the most grueling battle yet....
