But while the loss of the two cities would be a major blow to ISIS, it would not mark the end of the threat posed by the group, which is likely to return to insurgent-style attacks that were its hallmark in years past.
"In the next few days, we will announce the final victory over Daesh," Staff Lieutenant General Abdulghani al-Assadi, a senior commander in the elite Counter-Terrorism Service, told AFP in Mosul, using an Arabic acronym for ISIS.
However, there has often been a gap between the declaration of victory and the actual end of fighting in a given area in the course of Iraq's multi-year war against ISIS.
Iraqi forces launched the gruelling battle for Mosul on October 17, advancing to the city and retaking its eastern side before setting their sights on the smaller but more densely populated west.
The terrorists are now confined to a small area of Mosul's Old City, but its narrow streets and the presence of civilians has made the operation to retake it perilous.
Assadi estimated that there are between 200 and 300 ISIS fighters left in the city, most of them foreigners.
Iraqi forces captured the iconic Nuri mosque in Mosul on Thursday, the site where ISIS chief Abu Bakr al-Baghdadi made his only known public appearance in 2014, calling on Muslims worldwide to obey him.
ISIS blew up the mosque and the famed Al-Hadba (hunchback) leaning minaret last week as Iraqi forces closed in.
ISIS Escape Route Cut
Prime Minister Haider al-Abadi hailed the recapture of the mosque as a sign of ISIS impending defeat.
"We are seeing the end of the fake Daesh state," Abadi said in an English statement on his Twitter account.
The US-led coalition against the terrorists also said that the end of the battle was near.
He praised the Iraqi forces's "grit and determination" and said coalition support would help bring "an imminent liberation".
In neighbouring Syria, US-backed Syrian Democratic Forces (SDF) are fighting to retake Raqa, ISIS de facto capital in the country.
On Thursday, they cut off ISIS last escape route, trapping the terrorists inside the city.
"The SDF has been able to completely encircle Raqa," said Rami Abdel Rahman, head of the Britain-based Syrian Observatory for Human Rights, a monitoring group that relies on a network of sources on the ground.
On Friday, clashes were ongoing in several parts of Raqa and the coalition was carrying out air strikes, the Observatory said.
The SDF broke into Raqa on June 6 after spending months chipping away at terrorist's territory around the city.
Its fighters have since captured two eastern and two western districts of the city and are pushing towards its centre, where ISIS fighters are holding tens of thousands of civilians.
Around 2,500 terrorists are fighting in the city, according to British Major General Rupert Jones, a coalition deputy commander.