Transcript for Las Ramblas in Barcelona one day after terror attack

I am coming to you live from fossil or not legislate a 24 hours ago. This whole book evolved last bomb blasts what's thrown into complete else. Right here. It's the top end of last round loss. Boss Ron glass is a huge boulevard very very towards the if you can think of so easily say if you can thing called Fifth Avenue all the mile. In London it's that significant when it comes to tourists when it comes you. On people missing when it comes to locals. And just over 24 hours ago. A bun. And says this relocation. He started to proceed right down the boulevard for about 600 yards. One is what I think. They've managed to kill thirteen people and in just over 100. They all the casualty in Bethel figures that we have a but the moment. Just looking at the boulevard right now. If one's gonna cost like kind of man to spin it around. You wouldn't know how drugs that there was a significant incident. And Barcelona. Actually lesson today. The incident happened yesterday. Was the most significant terror attack this happened in spreading since the Madrid bombings in 2004. Over a 190 people died. Today. You concede that all will support us. Probably even more so than two days ago because a lot of people are content to flock to pay their respects to pay their tributes. Other tomorrow I have some idea you can see group of people that a flowers. Federal forties have a cards several well wishes. Several respects the thirteen people that died via. And then. The hot and me as well. It's also another area just up this direction by about twenty meters attributes have been paid a corner logically. What happened here was a significant intent to the way that the analysis is being built on the investigation is proceeding. On Wednesday evening. There was a huge explosion an explosion big enough to bring down a house. In a location pull out pocono which is about 200 kilometers down the coastline. From Barcelona in Spain southwest of here. Some explosion was initially reported to be a gas explosion however a as the hours and days of don't buy it is not a fool but this burial location. Walls the location of a terrorist cell network though discussions going on. With the counseling and police authorities which suggests that the location of the house where the speed being reported Baldwin's all. What's the very sense of a potential network that is operating inside a bite. The next day Thursday we then have the incidental loss rumble us where a man and a bottom. Drove. 600 ultimately down this boulevard and off Jason if you can raise his camera you can just see. How big the boulevard is just how many people. Our when this boulevard. I'm not sweat and thirteen people were killed and over a hundred were injured a lot of them French. That will a lot of Australians. That a lot of Greeks are not blends Irish and many many many casualties involved in this one American of the moment which is secretary of state. Was alluded to the fact that there was one American has been killed because company for the person. As yet. Then a couple of miles off this incident will take a walk around. A couple of hours after the incident allows run blast. This its own components which is about. 120 kilometers southwest of just before how can off. That it could. It was a another attendant medical attack. Proposal it was a mounted police say it was an outing on that we'll find suspects. In the holding. Suicide vest but suicide vests transpired. They were attempting. A similar sort of event to what happened right here thankfully the police become fluent in police's financial Ortiz what we're limbo. The incident that was about the carrying timber less and they dropped and killed. Third fight of the suspects. So far there have been to keep eight people to think soaring. Korean revolt which is about a hundred kilometers north of staying I'm born and how can off which is about Cuba 200 kilometers southwest of this is an incredibly significant. I floated through radio Spain has not. The level of radicalization. The level of violence. But we've seen so regularly and frogs in Paris and Brussels. I'm in the UK most recently. What what is significant. Is the fight that's again a very cool has been used to absolutely devastating effect of we have seen vehicles used. Being meets. Paying below the bridge attacks. We've seen vehicles views today we've seen trucks use. In voted. The real problem but authorities. Are having to struggle with. Not just in Spain but in loans for living Europe is the fact that Vick tolls on now becoming. The weapon of towards that being weaponized. Body. Ice system devices the big question for the investigation of the moment of his finest authorities are having to deal we've. Is. Just how extensive do the rich got. Where is. The next threat Blair is the next attack coming and at the moment the authorities. Are very much trying to. Rapidly understand through the intelligence authorities. Whether network is what the center of the network is. And who the major players were being determining. What happened yesterday what happened and could put us on what may happen in the future. Or very significant but I think what's really important also to note. Is that it's been thirteen years since a major incident a major terrorist incident. Happened in spite of I think that is significant when it comes to the realization. This financial authorities. How. Known about the growing threats all of this on this troubling to and from Syria. And since 2000 forces Madrid bombings in 2000 full dysfunctional authorities about the arrested about 700 people and convicted. Many more I'm putting jail over 120. So they've been working incredibly out of the losses he is but there is still a lot of the way to guide. Now what does this mean for America. A lot of the people we speak to in Spain in France in Europe. The problems and the problems are so much and blamed him that much more play because of than in America. Laurie because of the geographic disposition. But also because of the of the proximity in the historical relationships the safe roads of example of hot. So France isn't just concerned about what's happening in Iraq and Syria the threat from the least. It's also got a huge history in North Africa in Algeria and Mali I'm not significant when it comes to land the threat is coming from. Its front also has. A lot of experience we've got to capitalizations. A lot of problems with radicalization. On the way that marginalization has occurred within the current specifically Muslims inside frauds. Spain doesn't how about problem I'm you can speak to many people do all experts. Worked in Barcelona in Spain they will tell you that xenophobia has not taken over in space. They won't tell you there's a big difference between what is going on here in Spain to what is going on in frost on the rest of Europe. I think may be. Possibly French authorities the Belgian authorities that you don't Ortiz and dipping into what this global destruction that astonishing thing happened on May be honest I'm relevant or. About house but it actually went thirteen years without a prominent attack what brought back to the Herman now. Spanish investigators found authorities are working overtime to try and understand what the links will for yesterday's attack. I'm weather threat might be coming from next. Michael Kelly reporting from fossil and for ABC news.

This transcript has been automatically generated and may not be 100% accurate.