Iraq’s Prime Minister has declared an end to the IS caliphate after Iraqi forces captured the compound of a landmark mosque in Mosul in which the Islamic State group originally announced their caliphate.
"We are seeing the end of the fake Daesh state. The liberation of Mosul proves that," Haider al-Abadi said using the Arabic acronym for IS in a statement posted to twitter.
"We will not relent, our brave forces will bring victory," he added.
But even as the Iraqi leader issued his statement, heavy clashes continued to unfold in Mosul - filling field hospitals and forcing hundreds to flee.
The destroyed al-Nuri mosque retaken by Iraqi special forces on Thursday following a dawn push is a hugely symbolic win.
The site is where IS leader Abu Bakr al-Baghdadi made his only public appearance in July 2014, declaring a self-styled Islamic "caliphate", encompassing territories then-held by IS in Syria and Iraq.
Iraqi and coalition officials said IS blew up the mosque complex last week.
The Islamic State group has blamed a US airstrike for the destruction, a claim rejected by a spokesman for the US-led coalition who said coalition planes "did not conduct strikes in that area at that time".
The advances on Thursday come as Iraqi troops are pushing deeper into the Old City, a densely populated neighbourhood west of the Tigris River where IS fighters are making their last stand in Iraq’s second-largest city.
Last week, Iraqi forces launched the operation to retake the Old City’s narrow alleyways and dense clusters of homes, embarking on some of the most difficult urban combat in the IS fight to date.
IS now holds less than two square kilometres of territory inside Mosul, but the advances have come at considerable cost.
Damaged and destroyed houses dot the route Iraqi forces have carved into the congested district and the stench of rotting bodies rises from beneath mounds of rubble.
"There are hundreds of bodies under the rubble," said special forces Major Dhia Thamir, deployed inside the Old City.
He added that all the dead bodies along the special forces’ route were of IS fighters.
Special forces Major General Sami al-Aridi acknowledged that some civilians have been killed by airstrikes and artillery in the fight for the Old City.
"Of course there is collateral damage, it is always this way in war," he said.
"The houses are very old," he said, referring to the Old City, "so any bombardment causes them to collapse completely."
US-led coalition spokesman Colonel Ryan Dillon told reporters at the Pentagon that victory in Mosul was "imminent" and would likely occur "in days rather than weeks".
But, he continued: "The Old City still remains a difficult, dense, suffocating fight - tight alleyways with booby traps, civilians, and (IS) fighters around every corner."
Some 300 IS fighters remain holed up inside the Old City according to Iraq’s special forces along with an estimated 50,000 civilians according to the United Nations.
Nearly a thousand civilians fled Mosul’s Old City on Thursday, according to Col Ali al-Kenani, an Iraqi intelligence officer at a west Mosul screening centre.
While Iraqi forces have had periods of swift gains during the Mosul operation, combat inside the city has largely been gruelling and deadly for both security forces and civilians.
Clashes have displaced more than 850,000 people according to the International Organisation for Migration.