Iraqi forces are preparing for a push into the western part of Mosul to drive Daesh out of its last stronghold in the country.
Nearly 750,000 civilians living in west Mosul are at "extreme risk," the United Nations warned on Tuesday as Iraqi forces prepare for a push into the area.
"We don't know what will happen in western Mosul but we cannot rule out the possibility of siege-like conditions or a mass exodus," the UN's humanitarian coordinator for Iraq Lise Grande said.
Iraqi officials on Monday announced that government troops had taken complete control of eastern Mosul, 100 days after the start of their US-backed military campaign to remove Daesh from the city.
Mosul is Daesh's last major stronghold in Iraq.
The recapture of the city would deal a death blow to the Daesh presence in Iraq, with the next major target being the group's stronghold of Raqqa in neighbouring Syria.
The western part of the city could prove more complicated to take than the east as it is home to streets too narrow for armoured vehicles and Daesh's traditional redoubts.
Almost 180,000 people fled their homes before the Mosul offensive began on October 17.
Meanwhile, efforts to resume a normal life picked up in recent days in retaken areas of eastern Mosul. Many shops reopened and children started to go back to school on Tuesday.