director of fbi. He and other top law enforcement officials are tracking a steady stream of terror threats as we approach the anniversary of 9/11. We will analyze the latest. But first pierre thomas.... See More
director of fbi. He and other top law enforcement officials are tracking a steady stream of terror threats as we approach the anniversary of 9/11. We will analyze the latest. But first pierre thomas. Reporter: An al-qaeda plot to blow up a passenger plane. Lone wolf terrorists self-radicalized on the internet, striking without warning. And a cyber attack should we strike syria. It was chilling, the outgoing fbi director and the homeland security secretary said they are urgent in the final days in office. What keeps you up at night? A terrorist attack like the boston marathon. Threats to infrastructure via cyber and cyber networks and also threats to aviation which remains a target. Reporter: What the in the final days worries you most? The possibility of a plane being taken down, and the possibility of a weapon of mass destruction in the hands of a terrorist or terrorist group. Chemical, biological or cyber. The ability to impact the financial markets and energy sector. Reporter: And those are viable threats right now? Yes. Yes. Reporter: With the possibility of a strike on syria, cyber warfare has come to the forefront. The syrian electronic army, a group of hackers who support the assad regime claimed credit for attacking the new york times website and another site connect to the u.S. Marines. And concerns are converging with this week's upcoming anniversary of 9/11. The attack on benghazi happened on that very day. We always take the anniversary very seriously, even if we don't have something specific or credible. Reporter: So many threats, so much to guard against. Napolitano has this advice for her successor. Buy the large bottle of advil. And pierre is here, with brian ross and ali stoufan, former fbi special agent who investigated the bombsful uss cole, and other attacks. The new yorker said no one came closer to presenting attacks than you. We heard the secretary say there, no specific credible threat about an attack related to 9/11, but they are as worried as they have ever been. It's a convergence with syria, the 9/11 anniversary, and officials are very concerned about what they don't know. It's a nervous moment. They are checking the intelligence up to 9/11. As you recall last year, no specific credible threat and then benghazi. Benghazi. Right now, brian ross, we have seen reports of hezbollah perhaps planning retaliation against u.S. Interests in iraq, lebanon. The embassy evacuated. And these threats combined with the threat of a cyber attack. Hezbollah is capable, they make al-qaeda look like junior varsity. But in 25 year welcomes no record of going after u.S. Interests. And people we talk to -- you don't buy the new reports. I think more likely an attack on israel as opposed to the u.S. Interest. That would be a different kind of attack. Perhaps not just u.S. Embassies, hotels, airlines that appear to be american could be targeted. For the most part, hezbollah has no track record of that. The cyber attacks, the syrian electronic army, which appear to be about ten college-age kids in syria backed by -- pretty sure they're in syria. That's what we're told by u.S. Authorities, but they're not sophisticated. It's been disruptive, denied us marine dowd's columns, but not that sophisticated. More a nuisance. And you have come out with a report called countering violent extremism. And you write the achilles heel of american extremism is the failure to counter the narratives that inentire them like the boston marathon bombers. And 12 years after 9/11, if you look at al-qaeda and the area, it's not just pakistan and afghanistan, it's in other areas, it's south of yemen and syria and iraq. The narrative is spreading all over the muslim world from west africa to southeast asia. And what we need to include in our strategy in addition to the military, in addition to the law enforcement, in addition to the intelligence, we need to include countering the narrative of extremism. If groups like al-qaeda and its affiliate the continue to recruit, retain members, continue to find new blood, this war is going to go for generations. You think it should be tailored to the localities. What do we need to do? We need to deal with the problem in its own region. For example, the economy is a huge thing in africa. The resources, the economic disparities between regions, nigeria, for example. Look at it, it is operating in northern nigeria, and there's historical and economic problems. If you look at the situation in syria, it's mostly sectarian, or in iraq, it's mostly sectarian. In yemen, it has the roots between the north and south of yemen. The regional issues like in syria, for example, we cannot allow them to happen and say it's not going to come and haunt us down the road. Are officials absorbing the lessons? They absolutely are. But the wild card is the internet. You have people being radicalized on the internet. Boston, the fbi director said in the interview that he believed the people were radicalize on the internet, not from overseas. So they're having to worry about that in addition to what's happening overseas. People sitting at the computer, getting radicalized, and having the wherewithal to get the training to do an attack on them. How would you rate the level of concern to previous 9/11 anniversaries? At this point, according to the fbi as of last week, there were about 100 people in this country under active surveillance by the fbi. The bulk u.S. Citizens who are possible threats. Not enough information to arrest them, but worthy of being watched on an almost round the clock basis. Thank you all very much. Let's hope we get through this anniversary.
This transcript has been automatically generated and may not be 100% accurate.