Forces fighting the Islamic State group should be able to retake the IS-held cities of Mosul in Iraq and Raqqa in Syria within the next six months, according to the top U.S. commander in Iraq.
On a tour north of Baghdad Wednesday, U.S. Army Lt. Gen. Stephen Townsend said "within the next six months I think we'll see both (the Mosul and Raqqa campaigns) conclude."
Townsend also said he expected the fight for Mosul's western half to begin in days.
Iraqi forces have retaken about half of Mosul — the country's second largest city — since the operation was officially launched in October, following more than two years of coalition-led anti-IS operations around Iraq clearing supply lines and partially isolating the city. Last month Iraqi forces declared Mosul's east "fully liberated" and have since largely paused the fight.
Townsend, who heads the U.S.-led coalition against IS, said Iraq's military is still in the process of putting forces into place ahead of the push into western Mosul, but predicted operations would begin "in the next few days."
Closely backed by U.S.-led coalition airpower, Iraqi ground forces faced months of grueling urban combat in Mosul that at times brought the front lines to a standstill for weeks. But the pace of operations increased as Iraqi forces closed in on the Tigris River which roughly divides the city.
Townsend credited the quicker progress with better coordination and "lessons learned" on the part of Iraqi forces. But on the ground inside Mosul, Iraqi troops said as they neared the Tigris, IS fighters launched fewer car bombs and largely fled their advances — unlike the heavy resistance they faced in the first few weeks of combat inside the city.
Townsend said he expects that the fight for western Mosul will pose a particular challenge for Iraqi forces due to the older neighborhoods and narrower streets.
"It will be a more difficult fight, more constricted," he said.
At times during the Mosul fight, Iraqi forces experienced relatively high casualty rates among some of their most elite and well-trained fighters. Iraqi medics inside Mosul said during some of the heaviest fighting, Iraq's special forces were suffering around 20 casualties— both deaths and serious injuries — a day. Townsend said these high attrition rates were "a concern," but he didn't believe they would hamper the forces moving forward.
In Raqqa, significant ground military operations against IS have barely begun. The coalition has been targeting IS in the area for more than two years and U.S.-backed Kurdish-led fighters have been on the offensive in nearby areas, mostly north of the city, retaking just a cluster of surrounding villages over the past few months.
On Saturday, the fighters known as the Syria Democratic Forces announced the launch of the "third phase" of the Raqqa operation, which aims at isolating the city from the rest of IS-held territories before attacking the city itself. The announcement came a day after aircraft from the U.S.-led coalition destroyed two bridges on the southern edge of Raqqa, the de facto capital of IS' self-declared caliphate.
Iraqi and coalition officials have warned that the extremist group is still expected to pose a security threat in Iraq and beyond, even after it is defeated territorially. Townsend said he hopes U.S. forces can remain inside Iraq even after the Islamic State group is territorially defeated, unlike the withdrawal of forces that occurred in 2011.
"ISIL morphing into an insurgent threat, that's the future," Townsend said using an alternative acronym for the group. On a helicopter ride back to his Baghdad base Wednesday afternoon, he pointed to streets in the Iraqi capital below where he fought the predecessor to IS — al-Qaida in Iraq — and the landmarks targeted by the group with insurgent bombings.
When asked if he thought Iraqi forces would be capable of fighting IS when the group returns to its insurgent roots, he replied: "I don't know. We would have to refocus training in those areas."
U.S.-led coalition spokesman Col. John Dorrian, speaking to reporters from Baghdad during a weekly teleconference said he had not seen Townsend's remarks and declined to comment on the timing of the anti-IS operations.
Regarding the looming battle for Raqqa, Dorrian said, "What we would expect is that within the next few weeks the city will be nearly completely isolated, and then there will be a decision point" to launch an assault to retake the city itself.