BAGHDAD — The Iraqi air force recently dropped millions of leaflets on western Mosul alerting residents of pending operations to liberate the area from the Islamic State (IS). In late January, Iraqi forces supported by the US-led coalition retook eastern Mosul from the jihadi group. Counterterrorism units and others are currently gearing up to launch ground operations in the western half of the city. The area's dense population, old buildings and natural and architectural barriers will make its liberation challenging. It is also unlikely that IS will withdraw without putting up a fierce fight.

Western Mosul consists of 50 highly populated residential areas whose urban landscape is characterized by alleyways and narrow streets. Lise Grande, UN humanitarian coordinator for Iraq, has expressed deep concern about the fate of the 750,000 people trapped there. IS wants to use them as human shields and, therefore, will not allow them safe passage. Even if some were to manage to make their way toward the front, crossing it would not be easy.

The Tigris River splits Mosul into its eastern and western halves. In the battle for the city's eastern section, international coalition warplanes targeted the bridges across the river. The destruction of the Old Bridge on Dec. 11 severed the last connection between the two sides. Floating bridges will therefore be needed for military crossings, which will be a challenging undertaking at the wider parts of the river. This is the case in the north, whose relative openness makes it a good place for transferring military equipment.

Al-Monitor has learned from a senior military source who requested anonymity that counterterrorism units are preparing to establish three floating bridges on the river. That part of the mission will take place after international coalition airstrikes clear the area.