Updated

A top counterterrorism official said Friday the world still faces threats from Islamic State militants despite their territorial losses.

Nick Rasmussen, director of the National Counterterrorism Center, says the Islamic State group controls less territory, but added that the U.S. cannot breathe a sigh of relief from a diminished threat. He said officials still worry that a small number of skilled fighters could move out of the region and launch attacks in the West or in their homelands.

"We're not at the point where we can exhale or look at things and say that the threat condition has significantly improved," Rasmussen said.

He said there is going to be a lag time after success on the battlefield. IS has spread around the globe, suggesting that "we're going to be dealing with an enduring threat picture for some period of time," he said.

"Our view of this has changed a little bit in the intelligence community in the last several months," Rasmussen said. "At one point we were worried about this outrush — this massive outflow — of foreign fighters once the battlefield situation changed in Iraq and Syria and that western countries and countries in the region would be flooded with returnees. Speaking broadly, that's less likely."

He said that many — if not most — of the IS fighters will stay and fight and potentially die defending IS territory.

Despite rumors that IS leader Abu Bakr al-Baghdadi has been killed, Rasmussen said that he's seen nothing that suggests he has been removed from the battlefield.

Rasmussen spoke Friday at the Aspen Security Forum, an annual gathering of intelligence and national security officials and experts in Aspen, Colorado.