CAMP TARIQ, Iraq (AP) — Iraqi forces say they are continuing to push into the Islamic State-held city of Fallujah, having secured its outskirts.

Iraqi officers said Thursday that the large number of civilians in the city was slowing down the military operation, because it means fewer airstrikes can be carried out.

Brig. Haider al-Obeidi says “there were fewer civilians in Ramadi, therefore airstrikes are now less than during Ramadi operation.”

Iraqi forces are heavily dependent on airstrikes to achieve territorial victories against the Islamic State.