Transcript for New Threats from Al Qaeda Bomb Makers
Starting right now on ABC's "This week" -- security alert. U.s. Authorities on edge. I have never seen a threat matrix so serious. New airport worries this holiday week. Pierre Thomas with breaking details. And president Obama on the growing fears. In our exclusive interview. Are we under serious threat right now? Then, breaking overnight. Emergency move from the white house. Responding to a humanitarian crisis on the boarder. We're on the ground with the latest. Hillary under fire. Why is she charging nearly $250,000 to speak at a university? And breaking his silence. The father of the Santa Barbara shooter speaks out. What warning signs were missed? From ABC news, "This week" with George stephanopoulos begins now. Good morning. We're tracking two developing stories. Including a major new response from the white house to the humanitarian crisis on the southern border. And a new terror threat from the Al Qaeda group gaining more control of Syria and Iraq. Their advances raising security fears here at home. Pierre Thomas starts us out with the latest. Reporter: Right now, at this moment in Syria, Al Qaeda bombmakers are trying to design a new generation of explosives, including nonmetallic bombs. The U.S. Government is wrestling with how to respond. ABC news has learned the government is considering a number of new measures. Including asking overseas airport authorities to increase security. There is a new terror warning. Reporter:er this threat was initially discovered at the beginning of the sochi olympics. Prompting warnings of toothpaste bombs able to be smuggled on planes. Sources tell us evidence continues to come in indicating the bombmakers in Syria are still at work. This is exactly the kind of threat that keeps me up at night. Reporter: It's a potentially deadly convergence. Al Qaeda bombmakers have come to Syria from Yemen, at the time time thousands of foreign fighters, including some from Europe and the U.S., have come to join Al Qaeda groups. The fear is once the bombs are designed, the available manpower would be there to allow easy access to the U.S. What's more, terrorists are flowing back and forth over Syria's porous border with Iran. This week, after a classified intelligence briefing, senators issued a warning. One thing I learned from this briefing, our homeland is at risk. This is an urgent counterterrorism situation that our country faces. Reporter: It's an especially dangerous moment. I've been on the intelligence committee for ten years, chairman for the last four years. I have never seen a threat matrix so serious, so varied, and so many different streams of threat. Reporter: In addition to threats from abroad, U.S. Officials have to worry about so-called lone wolfs here at home. Extremists radicalized on the internet. Like the tsarnaev brothers who allegedly bombed the Boston marathon. As the fourth of July celebrations near, the security will be as intense as ever, even though there is no known plot right now. Pierre joins us now. We saw yesterday that the Libyan being charged with being the mastermind of the benghazi attacks, Ahmed Abu khattala was brought to federal court in Washington, D.C., after two weeks of entiinterrogation on a slow boat from Libya. How much is he cooperating? What are we learning? On the slow boat ride, he faced two kinds of interrogation. First a special team. They pressed for intelligence about imminent threats. Then about a week ago, he was read his rights by the FBI and they pressed him for answers. We're told he cooperated, giving some details but never admits guilt. This is a complicated prosecution ahead. He'll be treated like a common thug in civilian court. Prosecutors have to be able to show evidence that ties this guy directly to that case. The pressure is on the justice department to prove the case in court. He faces pressure. He's looking at the death penalty. He'll have to roll the dice and go to trial or plead guilty and perhaps save his own life. Okay, Pierre.
This transcript has been automatically generated and may not be 100% accurate.