Iraqi forces retook two more neighbourhoods in west Mosul on Thursday, tightening the noose around Islamist militants holed up in the Old City, commanders said.
"The forces completed the liberation of Al-Thawra neighbourhood," Sabah al-Noman, spokesman for the elite Counter-Terrorism Service, told AFP.
An officer with federal police forces also deployed in west Mosul confirmed that the neighbourhood, which lies just west of the Old City, had been retaken from the Islamic State group.
The Joint Operations Command coordinating the fight against the Islamist militants nationwide said the Nasr neighbourhood was also retaken on Thursday.
The head of Iraq's federal police, Raed Shakir Jawdat, also said in a statement that Iraqi forces had killed a senior IS operative, who had been in charge of chemical weapons for the group in Mosul, in a guided missile strike in the Zanjili neighbourhood.
A US official said on Wednesday that Iraqi forces working alongside US and Australian military advisers had been targeted in an IS attack that used a low-level chemical agent in west Mosul.
Major General Joseph Martin said nobody died as a result of the attack.
Iraqi forces in mid-October last year launched a huge operation, their largest in years, to retake second city Mosul.
They retook the side of the city that lies east of the Tigris river in January and launched a push on remaining IS fighters in western Mosul, which is more densely populated and has seen fierce fighting.
On the west bank, Iraqi forces control southern neighbourhoods and are slowly surrounding the Old City, whose narrow streets are expected to make federal operations very difficult.
An estimated 400,000 civilians are believed to still be there, unwilling or unable to leave because any escape would be too dangerous or because the Islamist militants are using them as human shields.
The loss of Mosul would be a death blow to the "caliphate" IS proclaimed after capturing the city in a massive offensive in June 2014.
According to an Iraqi military spokesman, the Islamist militants only control seven percent of Iraq, down from the 40 percent of the national territory over which they ruled three years ago.
The only two other significant towns IS still holds are Hawija and Tal Afar. The Islamist militants also control territory in remote areas of western Iraq, near the Syrian border.
Iraqi forces on Thursday launched a fresh push against IS-held villages there, as part of a months-old operation to retake areas along the Euphrates in western Anbar province.
A senior officer said the forces involved in the operation included the army, local tribal fighters and military advisers from the US-led coalition assisting Iraq in the anti-IS war.