Comey insisted the US had to act as if the Khorasan strike was “coming tomorrow,” but conceded that they don’t know whether they plan to attack “tomorrow or three weeks or three months from now.”
Khorasan, as a distinct faction, doesn’t actually exist, and analysts say the term was almost certainly invented by the United States. The term appears to be a way for the US to strike al-Qaeda’s Jabhat al-Nusra, a close ally to its “moderate” rebels, without officially saying they’re attacking them.
The US claimed Khorasan to be a faction of about 50 fighters, and also believes it killed 30 of them when it began the air war in northern Syria. The slain were al-Nusra members, which fueled considerable anger amongst the rebels, who accused the US war of being primarily to the benefit of the Assad government.
The US assessments of Khorasan as an imminent threat, given they are actually referring to al-Qaeda, undercuts their claims of having made major gains against al-Qaeda worldwide.