Iraqi forces have recaptured nearly 90 percent of west Mosul from the Islamic State (IS) militant group and other Islamist militants in the city are on the "brink of total defeat", officers said Tuesday.

Iraqi forces launched the massive operation to retake Mosul from IS nearly seven months ago, fighting their way to the city held by Islamist militants, retaking its eastern side and then attacking the west.

Brigadier General Yahya Rasool, spokesman for Iraq's Joint Operations Command, told a news conference in Baghdad that IS now controls just over 10 percent of west Mosul.

Both Staff Lieutenant General Abdulwahab al-Saadi, a senior Iraqi special forces commander, and Colonel John Dorrian, the spokesman for the US-led international coalition against IS, said that the end was near for Islamist militants in the city.

"They have two options: die and go to hell or raise the white flag. They have no third option," Saadi told AFP at his headquarters in Mosul.

"The enemy is completely surrounded," Dorrian told the news conference in Baghdad. "The enemy is on the brink of total defeat in Mosul."

The drive to retake Mosul has been supported by a campaign of coalition air strikes in and around the city.

Dorrian said that coalition strikes have destroyed more than 300 explosives-rigged vehicles in Mosul, as well as over 200 IS tunnels and more than a thousand Islamist militant fighting positions.

IS now controls just a handful of neighbourhoods around the Old City, one of the country's heritage jewels.

The area's narrow streets and closely spaced buildings make it difficult for federal forces to take on the Islamist militants, requiring them to fight on foot instead of from vehicles as they have previously done.

Half a million people are currently displaced as a result of the battle for Mosul, and some 250,000 civilians are estimated to still be trapped inside the city's west.

The number of those fleeing has been on the rise, with Thursday seeing around 20,000 people fleeing west Mosul, the Norwegian Refugee Council said, in the biggest single-day displacement since the operation began.

The presence of a large civilian population, which either chose not to leave or was prevented from doing so by IS, complicates any final assault to seal victory in Mosul.

While coalition air strikes have aided the advance of Iraqi forces, they have also reportedly caused hundreds of civilian casualties in the city.

Human shields have become a central feature of the vastly outnumbered Islamist militant' defences, and IS has stopped at nothing to deter people from escaping the city, including killing people who seek to flee.

Trapped residents reached by AFP inside IS-held areas have also recently warned that hunger was starting to kill more people than the fighting.

In eastern Mosul, life returned to a semblance of normality fairly quickly after Iraqi forces drove the Islamist militants  back neighbourhood by neighbourhood until the area was fully recaptured earlier this year.

IS overran large areas north and west of Baghdad in 2014, but Iraqi forces backed by US-led air strikes have since retaken much of the territory they lost to the Islamist militants .

But while the battle for Mosul is moving ever closer to its conclusion, the city's recapture will not mark the end of the war against IS in Iraq.

Losing Mosul would remove from Islamist militants' hands the largest Iraqi population centre still under IS control, and would be a major blow to their narrative that they have established a cross-border Islamic "state".

But IS also holds other territory in Nineveh province, of which Mosul is the capital, as well as in Kirkuk and Anbar, while Syria's Raqa is also controlled by the jihadists.