MOSUL, Iraq – The Islamic State group's hold on Mosul, Iraq's second-largest city, has shrunk to just two square kilometers (about one square mile). After more than eight months of some of the most intense fighting against the extremist group, Iraq's Prime Minister has pledged that victory is near.
However progress on the ground in Mosul remains incremental and IS continues to launch counterattacks in territory previously declared liberated.
The road to retake Mosul has taken Iraqi forces more than three years, cost the Pentagon more than $13 billion and left thousands of civilians and Iraqi security forces dead.
Below is a look at some of the key events in the fight against IS in Iraq.
A CALL TO ARMS
Just days after IS overran Mosul, Iraq's Shiite clerical establishment issued a call to arms, mobilizing thousands of men who were bolstered by Iranian supplies and training. Iraq's military had largely collapsed in the face of the militant onslaught and IS had reached the edge of the town of Samarra — home to a revered Shiite shrine and just 95 kilometers (60 miles) north of Baghdad.
These fighters — many from militias partially disbanded after the withdrawal of U.S. forces in Iraq in 2011 — quickly became more powerful than Iraq's military and have since been formally sanctioned by Iraq's government.
THE AIRSTRIKE CAMPAIGN
In August of 2014 the United States launched a campaign of airstrikes against IS. It was initially in support of Iraq's Kurdish fighters, known as the peshmerga, to protect the city of Irbil — home to a U.S. consulate and considerable other American interests.
The campaign steadily grew; months later the U.S. began conducting strikes in Syria and today more than 6,000 U.S. troops are in Iraq after nearly all had been withdrawn in 2011.
The air campaign quickly proved a decisive factor in the fight against IS. U.S.-led coalition airstrikes, reconnaissance and intelligence turned the tide against the militants and allowed Iraqi ground forces to begin retaking territory.
In March 2015, Iraqi forces launched the operation to retake Tikrit, the birthplace of former Iraqi leader Saddam Hussein some 150 kilometers north of Baghdad. The battle was the first major fight for Iraqi forces against IS in an urban setting, and Shiite militiamen participated alongside Iraq's conventional military.
The U.S.-led coalition withheld air support for Iraqi forces until militia fighters — many of whom are largely backed by Iran — partially withdrew from the city.
The Tikrit fight was relatively swift compared to the anti-IS operations that would follow, the key element being that the city was almost entirely empty of civilians.
The aftermath of the operation was marked by widespread allegations of looting and abuses carried out by the militia fighters in the majority Sunni city.
When Iraqi forces launched the operation to retake Ramadi in Dec. 2015, they embarked on the first fight against the extremist group in an urban environment that was still home to a significant civilian population.
Iraqi forces spent months surrounding the city — which lies deep inside Iraq's western Anbar province. The plan was to weaken IS fighters there by cutting supply lines, an approach to battling the militants that Iraqi forces would repeat in nearly every fight that followed.
Iraq's Shiite militia fighters did not participate in the fight and the coalition closely supported Iraqi ground forces with heavy airstrikes.
As Iraqi forces advanced in Ramadi, they emptied the city of civilians — resulting in massive displacement but allowing for swifter advances.
Within three months, Ramadi was declared liberated, but the victory came at an extreme cost to the city's infrastructure. Thousands of buildings were destroyed, key infrastructure was damaged and the city was rigged with hundreds of explosives.
The destruction was wrought by both coalition airstrikes and the militants' scorched earth tactics aimed at undermining government victories.
Less than an hour's drive from the Iraqi capital Baghdad, Fallujah was the first city to fall to IS in early 2014, months before Mosul.
The operation to retake the city had originally been planned to occur after Mosul as it holds relatively little strategic significance, but Iraqi forces changed course and began the operation to retake Fallujah in May 2016.
Fallujah was home to tens of thousands of civilians and had been under siege-like conditions for months.
As in Ramadi, Iraqi forces emptied Fallujah of civilians.
The operation caused massive displacement during the height of the Iraqi summer, forcing thousands of people to sleep in the desert without shelter and with little food and water.
Fallujah was declared liberated the following month, after IS defenses largely crumbled and hundreds of fighters fled into the desert. But hundreds of explosives prevented civilians from returning to the city until September.
The images of little government preparation for the displaced from Fallujah put increased pressure on the Iraqi government to prepare camps and aid ahead of the Mosul operation.