Video of President Obama: America's leading the war in the fight to degrade and ultimately destroy the terror group ISIL. On Monday our brave men and women in uniform began air strikes against ISIL targets in Syria. And they weren't alone.

Uma Pemmaraju: The President making his case to general assembly this week. President Obama is emphasizing his efforts to form an international coalition against terrorists in the Middle East today. But as the ISIS threat grows, we're learning more about other extremist organizations as well, like the al Qaeda-linked Khorasan group that has purportedly been planning an attack on the United States. Steve Emerson is a terrorism analyst and expert consulting with the FBI on matters of national security. We welcome you here to our studios today. Thank you so much for joining us, Steve. I've got to get your reaction to what's been developing in Oklahoma. I'm sure that you are quite aware of the concerns about home grown terrorists that are reportedly, you know, growing in number in different parts of the country. We just haven't seen recent incidents like this. But from your perspective, what do you think?

Steve Emerson: Well I think we actually - there have been more incidents than had been reported. There was one in New Jersey where a man who had actually killed four people and confessed that he killed them because of his desire to avenge the killings of Muslims by the United States. And that was not reported widely and the FBI was told to stand down. That was home grown terrorism. That happened in July. In this case, this still is an open question. But there's no doubt this guy was a fanatical Muslim radical. It was clear by his Facebook page, you know, pictures. Also the FBI found in his computer that they seized that he had been looking at radical Islamic websites. He had tried to convert his co-workers. He had made radical statements. Now the only question is what made him pop. Was it because he was disgruntled because he was fired or was it because he was carrying out calls to avenge the attacks against ISIS? We still don't know. But it's clear that the fact he decapitated someone, that is definitely unique to what ISIS or radical Islam calls for. There are two verses in the Koran that call for decapitation and that's unique to Islam [in being carried out today].

Pemmaraju: Let's talk about, in addition to ISIS we've been hearing a lot more about the group known as Khorasan, something we didn't really know much about until recently. These are all offshoots from Al Qaeda?

Emerson: It's a reaggragation of al Qaeda on a much smaller basis. They've got one agenda – attack the United States, primarily high-tech means through building bombs. Primarily through defeating technology on airplanes. And they reacquired the high-tech people who built those bombs, apparently the ones [that built] the underwear bomber in Detroit, the ones who built the cargo bombs going over the United States.

Pemmaraju: Some say they're more of a threat right now to us in the homeland than ISIS.

Emerson: Yes, there's no doubt. ISIS' agenda right now is to solidify its base, build the caliphate. Second stage, take over the Middle East Arab states like Saudi Arabia, sort of create an insurrection. And then attack the West. It has called for attacks against the West. but these are generalized calls, sort of loan wolves. But that's very dangerous because as someone said to me last night we're now entering the phase of a global jihad. Australia is experiencing the highest phase of threats that it ever has in its history. And the US or actually Britain now is the second highest phase. The United States I'm afraid is going to be entering that phase very shortly.

Pemmaraju: What's changed in terms of recruiting? Why is it so, you know, exciting for some of these young people to go ahead and be part of these groups?

Emerson: First of all they're really pre-selecting people now that are willing to die as opposed to previous jihad wars where anybody could volunteer. And [as far as] the arrests that we have seen since 9/11--and there have been hundreds of arrests, some 90 convictions for terrorist plots--most of them have been people that have been willing to carry out attacks, not suicide bombings, but rather remote detonations of bombs. In the case of ISIS, these are volunteers that have vetted and vetted twice. Once in the United States or in Europe, and then on the borders with Syria. And they're vetted to see if they're willing to carry out suicide bombings.

Pemmaraju: Sort of more of an elite group so to speak?

Emerson: Sort of an elite suicide group. So they're willing to carry out really vicious bombings. When they come back to the West, either Europe or the United States, that's when they're going to cause the most damage. And that's the biggest fear, when the generalized calls go out and say carry out as many killings as you can, they are willing to do so.

Pemmaraju: Scary. Steve Emerson, great to see you. Thank you for joining us today.

Emerson: You're welcome.