WASHINGTON (AP) " The urban battle to retake Iraq's second largest city from Islamic State militants that will unfold in the next two or three months will be "long and difficult," the head of the Defense Intelligence Agency said Thursday.
Lt. Gen. Vincent Stewart noted that the militant group has had at least two years to figure out how to hold Mosul.
"Urban warfighting is not easy," he said at a national security conference in Washington. "This is a large city that has had at least two years to prepare to defend its position."
"If an adversary is willing to stand and fight in an urban environment, and you are least limited in the amount of casualties you can impose, it is going to be a long and difficult battle as it unfolds."
He agreed that there is a danger in succeeding too quickly on the battleground before governance and humanitarian resources are in place.
Late last month, Iraqi forces retook a town 45 miles south of Mosul. A string of towns south and southeast of Mosul have also been recaptured as part of an operation aimed at eventually unseating IS from Mosul itself.
"We've pushed ISIL out of a good bit of territory," Stewart said using another acronym for the militant group. "We're now starting to isolate ISIL, and I would imagine that the operation will unfold sometime in the next two or three months."