When asked if there were plans on how the US could react to ISIS' possible seizure of Mosul, Dempsey responds, "Well no, there were not."
"There were several things that surprised us about ISIL," Dempsey explains. "The degree to which they were able to form their own coalition, both inside of Syria and inside of northwestern Iraq, the military capability they exhibited, the collapse of the Iraqi Security Forces ... In those initial days, there were a few surprises."
General Dempsey's remarks come a week after ISIS made some of its most significant gains since it rampaged through Iraq last summer.
Earlier last week ISIS gained significant territory in Anbar, Iraq's largest province, including the provincial capital of Ramadi. The group also took the ancient city and Assad regime stronghold of Palmyra, in Syria.