ROBERT SIEGEL, HOST:
Police are searching for more members of what appears to be an ISIS-trained cell behind last week's attacks here. Their investigation is increasingly shifting to Belgium, to a largely North African neighborhood called Molenbeek just outside of Brussels. NPR counterterrorism correspondent Dina Temple-Raston is with me in Paris, and she has the latest in the investigation. Dina, what are we learning?
DINA TEMPLE-RASTON, BYLINE: Well, police have cast a wide net to identify the men who were behind the attacks. They've been searching for days for a 26-year-old French national who has been living in Belgium. His name is Saleh Abdeslam, and there's an international arrest warrant out for him. You know, ironically, he was stopped by police near the Belgian border hours after the attack. But at the time, they hadn't yet identified the attackers or put together that in fact his brother had been one of the suicide bombers who detonated a vest inside a cafe in Paris.
SIEGEL: Now, earlier today, police said that they had a new suspect they're searching for. Do we have any idea how big this plot really is?
TEMPLE-RASTON: Well, so far, this has involved the seven attackers who died, Abdeslam, this other suspect - that's nine so far. And then sources told NPR that they believe the plot is wider than that. It could involve more than a dozen people. But again, this is early days and they're still piecing this all together.
SIEGEL: Dina, let's talk about this Belgian connection. This neighborhood of Molenbeek, it's come up in terrorism cases before, hasn't it?
TEMPLE-RASTON: Molenbeek is a well-known haven for extremists in Europe. It has a huge North African population and the unemployment there is very high. Now, the area has been linked to at least four terrorist attacks in just the past two years. Back in January, the gunmen who murdered shoppers in a kosher supermarket just two days after the attacks on the Charlie Hebdo satirical magazine, he bought his weapons in Molenbeek. In 2014, the man who shot up a Jewish museum in Belgium, he bought his guns there, too. And then if you remember that shooting on the high-speed train this summer in August, the man who was tackled by some Americans when his gun jammed, he was from Molenbeek, too. So a source close to the investigation told me that it's well-known throughout Europe that if you're looking for a gun or you're looking for explosives, Molenbeek is one of the places you go.
SIEGEL: Dina, France has been on a heightened security footing since January. And yet, the attackers clearly were able to get lots of guns and explosives into France. What went wrong?
TEMPLE-RASTON: Well, from a distance, this may seem like a massive intelligence failure until you realize that with the open borders in Europe, driving weapons from Brussels to Paris is a little like driving illegal guns from Virginia to, like, New York. People don't have to go through border crossings anymore. I mean, we do that when we fly into airports and we see the people with EU passports standing in those much shorter lines. But if you're driving, the way you'd know you passed into France from Belgium is a big sign that says Bienvenue a la France, welcome to France, not some border guard. And criminals and terrorists are taking advantage of that.
SIEGEL: Just in the last few weeks, we've seen ISIS take responsibility for the downing of a Russian civilian plane near Sharm el-Sheikh, then the twin bombings in Lebanon, then a day later these attacks in Paris. President Obama said before this Paris attack that ISIS was contained in Syria and Iraq. How did ISIS get here?
TEMPLE-RASTON: Well, I know this seems like something unpredictable, but what we're actually seeing is the progression of a terrorist organization. They almost all start out with a regional focus. Al-Qaida had the Russians in Afghanistan, Al Shabaab was focused on getting Ethiopians out of Somalia, and ISIS was focused on Syria and Iraq. But as they get more powerful, they look outward to take on other challenges. It's almost as if there are successive graduations. Elementary-level terrorist organizations focus on small, local problems. They graduate to more complicated regional issues and then they begin to have broader aspirations. So it's almost a natural progression. That's why counterterrorism officials say they're always concerned about regional terrorist organizations because inevitably, as they develop, they turn their sights on the West.
SIEGEL: That's NPR's Dina Temple-Raston with me in Paris. Dina, thanks.
TEMPLE-RASTON: You're welcome. Transcript provided by NPR, Copyright NPR.