- Matt Olsen is the former director of the National Counterterrorism Center.
- His analysis finds the threat from the Khorasan group remains even after airstrikes.
The former head of U.S. counterterror operations said Tuesday the "imminent threat" posed by an al Qaeda offshoot in Syria hasn't lessened after a U.S. air campaign there.
Speaking to CNN's Jim Sciutto, Matt Olsen said by his analysis the threat from the Khorasan group "is still in the same place as it was before" President Barack Obama ordered airstrikes against the terror operation last month.
"This group was in a position to train without any sort of interference, they were able to recruit operatives," said Olsen, who stepped down as director of the National Counterterrorism Center in September. "We saw that they were looking to test explosives. So they were in the advanced stages of plotting. They had both intent and that capability that put them nearing an execution phase of an attack."
President Obama announced strikes against Khorasan in September at the same time he began the mission to "degrade and destroy" the Islamic State terror group in Syria and Iraq. At the time, senior officials described the threat posed by Khorasan as "imminent."
In the days after the strikes, the Pentagon said they believed the mission had "degraded, damaged, destroyed some of their capabilities," but didn't specify whether the threat was taken out altogether. No subsequent strikes against Khorasan have been announced by the U.S. military.
Olsen said on Tuesday the types of individual who have joined Khorasan -- "hardened, seasoned veterans" -- made it unlikely the threat had diminished.
"I think it's unlikely that threat's altogether been eliminated," Olsen said, adding that some senior leaders with the group had been killed.
Before the strikes began in Syria, U.S. government officials had barely acknowledged the presence of Khorasan, which formed from former al Qaeda members. Sources have said the group has the same aim as ISIS: recruiting and training foreign fighters who could return home to stage attacks.
While Olsen said foreign fighters present a broad risk to Americans' security, the potential for so-called "lone wolf" attacks by unaffiliated terrorists also worries officials.
The propaganda circulated by ISIS online could allow Americans to be motivated by the group without ever leaving the country, he said.
"The other issue is somebody in the United States, who never leaves the United States, simply sits in their basement reading some of this hateful propaganda that ISIS puts out," he said.
"The concern is that somebody just reads that and they have something in their own mind that makes them think that's what they want to do. They would seek to carry out what we would think would be a relatively small scale attack, but a lethal attack nonetheless."