A hundred days into a major push to recapture Mosul from ISIL, the Iraqi army has said it is gearing up for an offensive to take the city's western half, even as troops are still battling the armed group to take full control of the eastern sector.

The Popular Mobilisation "is preparing an operation in the next two, three days, to back up the operation to retake the right bank" of the city, on the western side of the Tigris river, Mosuliya TV cited General Abdul Ameer Rasheed Yarallah, commander of the anti-ISIL campaign, as saying on Tuesday.

Popular Mobilisation is a coalition of predominantly Iranian-trained Shia groups, formed in 2014 to take part in the war on ISIL, also known as ISIS.

The armed militia became officially part of the Iraqi armed forces last year.

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Yarallah's comments came as the UN and several aid groups warned on Tuesday that an estimated 750,000 civilians are still living under "sharply deteriorating" conditions in ISIL-held western Mosul.

"The prices of basic food and supplies are soaring. Water and electricity are intermittent in neighbourhoods and many families without income are eating only once a day. Others are being forced to burn furniture to stay warm," Lise Grande, the UN Humanitarian Coordinator for Iraq, said in a statement.

The operation to recapture Mosul, ISIL's main stronghold in Iraq, was launched on October 17, backed by air strikes and advisers from a US-led coalition against the armed group.

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ISIL, which stands for Islamic State of Iraq and the Levant, took control of Mosul, Iraq's second-largest city, in mid-2014.

But even as they prepare to retake western Mosul, Iraqi forces continue to fight ISIL fighters in the eastern part of the city.

On Monday, the defence ministry said it had reclaimed Mosul's eastern sector, but later retracted the statement.

'Dramatic and horrific'

As the anti-ISIL offensive in Mosul enters its 100th day, the humanitarian situation continues to deteriorate amid ongoing fighting and a lack of essential supplies.

To date, some 180,000 people have fled eastern Mosul, according to the UN. Yet, more than 550,000 people have stayed in their homes, and they do not have adequate water, food or healthcare.

"It was tragic, there was no food, no water, nothing. Thank God, the forces came and liberated us," a resident of Hay al-Arabi, in eastern Mosul, told Al Jazeera.

A main water pipe was damaged in the fighting, leaving people without clean water, or forcing them elsewhere in their district as Iraqi forces get rid of unexploded ammunition.

In one military hospital on the outskirts of Mosul, medics have started treating civilians with chronic diseases, as well as wounds from the fighting, receiving more than 200 new patients a day.

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People are also worried about what will happen once Iraqi forces move into the west of the city.

"Given that western Mosul is now covered on all sides, from the river and all around it, the ability for people to escape or to leave the city is now very limited," Peter Hawkins, a representative for the UN children's agency, or UNICEF, in Iraq, told Al Jazeera.

"The situation has become dramatic and horrific."