Iraqi troops and their allies are getting closer and closer to Mosul. Forces at the head of the advance, approaching the city from the east, have even crossed into the city's outskirts. Islamic State fighters in the heart of Mosul have begun to prepare for the impending battle, and based on satellite imagery obtained from our partners at AllSource Analysis, it appears as if the jihadist group has formed a formidable defensive line along the southern edge of the city's center.
The photographs above, taken Oct. 31, show that the Islamic State has cleared a wide swath of terrain to the north of Mosul airport, along the western bank of the Tigris River. Nearly all of the buildings in the airport complex and the former military base to its west have been leveled. (Though Mosul's sugar factory is still standing, its facilities seem to have already been struck by coalition airstrikes.) By destroying the buildings, the jihadists are likely trying to transform the edge of Mosul's fortified city center into a wall from which they can target approaching adversaries. The large open areas the Islamic State has cleared to the south of its positions will enable it to watch and engage advancing forces from a greater distance.
Meanwhile, the Islamic State has also erected a long line of barricades on roads leading into the city. The group has placed concrete blocks — perhaps portions of concrete walls — and other rubble in the streets to prevent vehicles from navigating them. However, the militants have opted against reducing mobility in several areas of the city for now. They have fashioned ready-made barriers that are currently lining both sides of the roads that are still open, and they could easily tip them into the streets once the battle draws near.
The air power and artillery fire that Iraqi forces can bring to bear will significantly reduce the Islamic State's chances of maintaining its hold on Mosul. Nevertheless, the jihadists' defensive measures will pose a substantial tactical challenge to the converging forces. Iraqi troops will either have to adjust their course to avoid running into the Islamic State's positions head-on, or accept the risks of crossing open terrain to reach the dug-in jihadist fighters.