Hundreds of square kilometers of territory and as many as nine villages had been taken from ISIS control.
Since attacking at dawn, Iraqi forces had made “substantial progress along several avenues of advance,” in the “largest battle (Iraqi forces) have taken on to date,” US Central Command spokesman Col. John Dorrian told CNN’s Christiane Amanpour.
Less than 24 hours in, the Iraqi military says it has inflicted “heavy losses of life and equipment” and CNN’s Nick Paton Walsh, on the ground just outside Mosul, ISIS’ remaining stronghold in the country, says that some of the day’s skirmishes have been “staggering.”
On one approach road, Peshmerga forces seeking to liberate a village on the outskirts of the city return ISIS fire with old, cumbersome weapons. There is panic as an ISIS suicide car bomb careens toward their position, and rockets are unleashed to take it out. It’s hit on the third time of asking.
On the whole, however, Peshmerga commanders encountered less resistance than expected, Paton Walsh said.
Paton Walsh was caught in an exchange of gunfire as he was filing a dispatch. The CNN team, the first Western media outlet to travel along the road into Mosul during the offensive, were unharmed in the exchange.
Peshmerga forces, which are playing a key role in the offensive, cleared nine villages in an area measuring approximately 200 square kilometers. Forces east of Mosul also secured control over a significant stretch of the Erbil-Mosul road, a key strategic route, the General Command of Peshmerga Forces of Kurdistan Region said.
Dorrian said that most of the resistance had come in the form of mortar and small arms fire, and improvised explosive devices (IEDs).
Iraqi leaflets dropped from planes onto the city have urged Mosul’s residents to shelter in their homes and to disconnect gas lines. Several months ago, Iraqi Prime Minister Haider al-Abadi had told CNN that he was “counting on” Mosul’s population to rise up against their oppressors when the operation commenced.
For ISIS, the capture of Mosul formed a vital part of its self-declared caliphate across swaths of Iraq and Syria, in addition to assaults on Ramadi, Tikrit and Falluja. One by one, in the past two years, coalition forces have reclaimed those cities.
While the Iraqi coalition is overwhelmingly superior in terms of numbers and firepower — with forces numbering around 100,000 and air support from roughly 90 coalition and Iraqi planes — “ISIS is showing that it’s very willing to put up a fight,” Paton Walsh said.
The terror group is deploying suicide bombers against advancing Iraqi forces, CNN’s Arwa Damon, also on the ground in northern Iraq, reports.
ISIS, which has been on the back foot in Iraq and some parts of Syria in recent months, has constructed elaborate defenses in the city, including tunnels, barriers and trenches, as well as planting IEDs.
Paton Walsh’s team saw an ISIS fighter pop up from a tunnel outside the city in an attempt to ambush Peshmerga troops, before blowing himself up — an indication of how committed some of the ISIS militants are, which will no doubt slow the advance.
“Mosul is going to be a very tough battle,” Dorrian said. In addition to airstrikes and logistical support, he said that the US is providing advice to Iraqi allies.
For now, violence is limited to the villages on the city’s outskirts. But the coalition is expected to encounter fierce resistance from thousands of ISIS fighters in Mosul’s urban center, armed with car bombs and IEDs.
One of the challenges will be coordinating and keeping the Peshmerga and militia forces on-side. Kurdish and militia troops have been ordered to stand down and allow Iraqi government troops to enter the city.
While as many as 100,000 troops will play a role in the operation, not all will be directly involved in the assault on the city. Some will secure positions behind the front lines or play other supporting roles.
The force includes 54,000 members of the Iraqi Security Forces and 40,000 Kurdish Peshmerga fighters. There also are 14,000 members of paramilitary units — 9,000 Sunni fighters, and 5,000 from other minorities including Christians, Turkmen and Yazidis. Shia paramilitaries will not be involved in the assault on Mosul, but will be tasked with securing areas around the city instead.
Before ISIS seized Mosul in June 2014, the oil-rich city had more than two million residents. Today, about one million remain.
US military officials have estimated up to 5,000 ISIS fighters are in Mosul, but the terror group’s supporters say there are 7,000.
Humanitarian crisis looms
Refugee agencies are anticipating that the fight for Mosul could trigger a humanitarian crisis as up to a million people could be displaced.
The UN High Commissioner for Refugees (UNHCR) has five camps ready to shelter up to 45,000 Iraqis displaced by the offensive and it could handle up to 120,000 if the agency finds sites for more camps.
CNN’s Nick Paton Walsh, Hamdi Alkhshali, Arwa Damon and Ben Wedeman reported from near Mosul; Max Blau, Emanuella Grinberg and Tim Hume contributed to this story.