The long-anticipated campaign to reclaim Mosul from the Islamic State began Monday. It is the largest military operation in Iraq since U.S. forces left five years ago.
The Battle for Mosul
![Iraq's elite counterterrorism forces gather ahead of an operation to re-take the Islamic State-held City of Mosul, outside Erbil, Iraq, Oct. 15, 2016.](https://gdb.voanews.com/C4A116F1-B695-4A29-B35C-B5187A0E4343_w1024_q10_s.jpg)
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Iraq's elite counterterrorism forces gather ahead of an operation to re-take the Islamic State-held City of Mosul, outside Erbil, Iraq, Oct. 15, 2016.
![Peshmerga forces gather on the east of Mosul during preparations to attack Mosul, Iraq, Oct. 16, 2016.](https://gdb.voanews.com/AE4A4724-1E87-4EF5-9A94-BBAC6681CF35_w1024_q10_s.jpg)
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Peshmerga forces gather on the east of Mosul during preparations to attack Mosul, Iraq, Oct. 16, 2016.
![Iraqi special forces soldiers deployed for an offensive to retake Mosul from Islamic State militants prepare to move out from a camp near Khazer, Iraq, Oct. 14, 2016.](https://gdb.voanews.com/9ADED08C-AF8C-4419-BACB-60B540D999AD_w1024_q10_s.jpg)
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Iraqi special forces soldiers deployed for an offensive to retake Mosul from Islamic State militants prepare to move out from a camp near Khazer, Iraq, Oct. 14, 2016.
![Peshmerga fighters are seen in Khazer, west of Erbil, Iraq in this still frame taken from video, Oct. 17, 2016.](https://gdb.voanews.com/82B1A6A2-3310-4E2D-8F66-C3AF977683B7_w1024_q10_s.jpg)
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Peshmerga fighters are seen in Khazer, west of Erbil, Iraq in this still frame taken from video, Oct. 17, 2016.