It is Iraq's second-largest city and has been under Islamic State control for the past two years.
But as a convoy of trucks laden with heavy duty tanks made its way towards Mosul, the country's prime minister, Haider al-Abadi, was promising the end was near for the IS occupation.
"And now we are fighting at the entry of Mosul. As a result, very soon, we promise that we will get rid of Daesh, and we also promise that, in 2016, we will liberate Mosul."
Then, just hours later, Mr al-Abadi wrote on Facebook:
"Dear people of Iraq, the hour of liberation has come, and the moment of the great victory is near. I announce today the beginning of the operation to liberate the province of Nineveh."
Mosul, located in Nineveh, is the country's second-biggest city, the largest with a mainly Sunni Arab population and the largest under IS control.
IS overran the city in mid-2014 as it began a lightning quick offensive and seized large parts of Sunni Arab northern and western Iraq.
Weeks later, the group's leader, Abu Bakr-al-Baghdadi, made a rare public speech from Mosul's Great Mosque after the organisation proclaimed him the caliph.
The battle for Mosul is expected to be a brutal struggle, with IS believed to have 6,000 fighters ready to defend the city and with a force of 30,000 coalition fighters surrounding the city.
Former chief of army Peter Leahy, now director of the National Security Institute in Canberra, says it will be a long struggle.
"We know Mosul's a very large city, it's a very complex city. There's going to be fighting in an urban area, which is about the hardest fighting that you can ever do. And the people in Mosul, the civilians there, are going to get caught up in the fighting. We've seen this in Fallujah, in other places, in Ramadi. There will be a lot of damage. There will be a lot of civilian casualties. And the United Nations is warning there will be a lot of humanitarian disasters, a lot of people moving out, and they're going to have to be looked after, and, eventually, they'll have to be resettled in the city. It's going to be a long struggle for everybody involved in this."
The Iraqi Defence Ministry has dropped tens of thousands of leaflets over the city warning civilians to avoid any known locations of IS militants.
Professor Leahy says the push on Mosul is a sign of the resurgence among the Iraqi armed forces after they meekly surrendered Mosul to IS, also known as ISIS, two years ago.
"Now we've seen that they've worked their way up, they've got the equipment, they've got the training, morale is back, and they're fighting for their country, and good on them. They need to take Mosul back. They need to eject ISIS physically from Iraq and then not only rebuild Mosul but they need to rebuild Iraq."
It is a challenge faced, too, in war-ravaged Syria, where IS has also lost the momentum.
Turkish-backed rebels have captured the small northern Syria town of Dabiq.
And rebel fighter Rami Boutran says he is confident of more victories.
"I am the military leader of the Hamza Brigade. We are now in Dabiq, thank God, and we've been able to capture other towns like Souran. God willing, we will comb the area until we reach Raqqa and beyond."
But Peter Leahy says retaking Dabiq itself is a particularly significant development.
"ISIS has an apocolyptic view of the world, and they believed that Dabiq was the area where the final battle, this climactic battle, would be fought between the good and evil -- and we're the 'evil' lot. So to be able to retake Dabiq will be a symbolic loss to them."
But regardless of the advances against IS, analysts are quick to remind that its ideology will remain a global threat, with or without Mosul, with or without Dabiq.
