ISIS militants also used the same technique in Raqqa city in Syria. Many experts fear that such technique might force the coalition troops to randomly shell civilian areas.
Other concerns might be that ISIS militants could use street war techniques to corner the Iraqi forces in tight spots, taking advantage of the old city's narrow streets and alleys that hinder security forces from using military vehicles or an aerial support to expel the militants from the city. Iraqi security forces have recurrently affirmed that war in the densely-populated section of the city will guarantee safety of civilians and their residential areas.
This may lead to a total bloodbath as ISIS militants have reportedly dug tunnels under the city to roam it without detection and to ease access for their snipers to hunt down Iraqi soldiers without being seen from the ground or from the sky due to their covers at the rooftops of the city.
This comes in the wake of the Iraqi Army advancement on Mosul airport and capturing large swaths of it, with reports indicating that the Iraqi Forces have fully captured it.