End of ISIS: U.S. and Iraqi Forces Prepare for Final Battle After Surrounding Old City

The Iraqi army and its allies have completely surrounded the Islamic State militant group (ISIS) in Mosul's Old City, the jihadists' final area of influence in what was once their largest city.

After more than eight months of fierce fighting, an alliance of Iraqi military, Kurdish forces, majority-Shiite Muslim militias backed by Iran and a U.S.-led coalition have forced ISIS militants back to the last district claimed by the ultraconservative Sunni Muslim group in its stronghold of Mosul. Lieutenant General Abdul Amir Yarallah, commander of the U.S. and Iraq's Joint Operation of Command in Ninevah distict, said Thursday in a statement that his forces had defeated ISIS in the neighboring district of Bab Sinjar, cutting off every possible route of escape for the jihadists, according to Iraqi News. Now, the military and its allies are preparing to storm the nucleus of ISIS support in Iraq.

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Iraqi Brigadier General Saleh Harz, commander of the 34th brigade of the army's 9th armored division, told Iraqi news outlet Al Mirbad Thursday that his forces had reached the right flank of the Old City after violent clashes with ISIS, and that Iraqi forces would enter the Old City's main gate within the next two days. Harz's armored division will reportedly stay behind, because the historic district's streets are two narrow for the military's vehicles to pass through. Instead, Iraq's elite Counter-Terrorism Service and Rapid Response Forces are set to face off against the estimated few hundred fighters that remain in Mosul's Old City. First, however, Harz said soldiers would need to allow as many as possible of the 200,000 civilians believed to be trapped behind ISIS lines to flee.

ISIS's takeover of Mosul in 2014 drew international attention and came amid the height of the group's territorial claims in the nation. The jihadists had come together from a 2006 merger of other fundamentalist organizations, including Al-Qaeda in Iraq, and took the name ISIS after branching out to neighboring Syria in 2013. A year later, they overran the Iraqi army in a number of key cities, at one time claiming as much as 45 percent of the country. It was at Mosul's al-Nuri mosque that the group's elusive leader, Abu Bakr al-Baghdadi, made his only known public appearance, to declare ISIS a global network.

Now, the mosque and the surrounding Old City are one of the group's last remaining outposts after its fighters were ultimately beaten back in recent years by an array of local forces supported by a U.S.-led coalition and Iran. After managing to secure the eastern half of the city earlier this year, the fight for the west has seen a sharp escalation in violence. Last month, Iraqi forces made a major breakthrough against a number of ISIS-held neighborhoods that saw ISIS defense lines collapse, and helped set the stage for the upcoming operation to enter the Old City itself.

While a defeat in Mosul would effectively signify an end to the group's presence in Iraq, ISIS militants do maintain minor pockets of support in the province of Kirkuk and in certain areas along the country's border with Syria, where the group's other half faces its own existential challenges. Outside of Mosul city, the Population Mobilization Force, an irregular grouping of majority-Shiite Muslim militia groups that enjoy Iranian support, have managed to reach the Syrian border west of Mosul and have begun charging to the south. The militias reportedly managed to fend off a large-scale ISIS attack launched Wednesday at dawn in the desert south of Mosul.