Mosul, Iraq - Last month, Iraqi forces resumed their assault on the city of Mosul, which has been under the control of the Islamic State of Iraq and the Levant group (ISIL, also known as ISIS) since 2014.

The eastern side of the city was recaptured in a three-month offensive that ended in January, but the west, with its densely populated maze of narrow streets, is thought to pose a greater challenge.

Surrounded by a diverse array of Iraqi forces, the remaining ISIL fighters are digging in for a fight to the end, using car bombs, snipers and grenade-laden drones to slow the troops' advances.

Meanwhile, civilians have been fleeing Mosul in droves, with tens of thousands more expected to be displaced as fighting continues in the weeks ahead.