Breaking news continuing to unfold in france as we come on the air tonight. At least 120 people confirmed dead at this hour, as well as eight attackers. Scenes of carnage at six paris. Sports stadium. Machine guns at a rock concert. These socalled soft targets all chosen to have the bloodiest impact on people enjoying a festive friday night out. Carnage and horror on the streets of paris tonight. As ambulances continue to cart away the scores of wounded, overwhelming hospitals. With all these patients, we try to save some. It was an awful night. Reporter parisians now reeling from the deadliest terror attack in that nations history. We saw people running up the street. We turned around and ran for our lives. Reporter a highly coordinated killing spree. Unprecedented and unimaginable. Consisting of suicide bombs, shooting rampages, and multiple explosions throughout the city. I sat with one friend and we immediately heard really loud gunshots. Everybody dropped to the floor in confusion. Reporter at the center this theater, the bataclan, where the American Band eagles of death metal was performing to a soldout crowd. I was, you know, enjoying the concert. And the band playing, you know, they were in the middle of a song. Then all of a sudden we heard shots. People were running away. Then all of a sudden people on the balcony where i was sitting started getting up and panicking. And thats when i ducked, you know, i went behind the seats and the friend i was with i took her hand and we kind of made our way to an exit. Reporter michael dorios brother was performing onstage. They saw men with machine guns just kind of shooting at anything and everything. Just the venue. Reporter the concertgoers trapped inside. Everybody ran out in a panic. We all ran out in different directions. The attackers screaming allahu akbar and syria. I saw a couple of guys woundeded. I saw a guy with a white shirt drenched in blood. I heard about 12 loud bangs. And shortly after, ambulances rushing towards the theater. I was able to follow some of them. And i could see firefighters evacuating people from the second floor, taking them to this makeshift hospital, makeshift hospital and cafe nearby. I saw people, you know, coming out, looking terrified, with blood all over their tshirts. Reporter the french elite police storming the theater, dozens killed, including four terrorists, three from detonating their suicide belts, one shot by police. They had the equipment, they had locations that they had picked, and they picked friday night in paris to launch. So yes, all of those things are coordinated. Probably by their standards it was a successful night. Reporter in all, at least six separate attacks across the city of lights. Bloodshed as gunmen opened fire on popular restaurants. Charlotte brea was inside. I was holding on to a woman on the floor with me. I was asking her if she was okay, holding her hand. And i i realized she wasnt breathing or she was struggling to breathe. As i could look up when i felt safe enough to look up, i realized there was a podol of blood surrounding her and i think shed been shot in the chest. Reporter bodies draped in white sheets in the street. Seth porges witnessing the aftermath. The first thing i see is a man with a towel or shirt wrapped around his bloody hand and blood dripping from it. I see police with guns huddled behind vance. Dozens of firefighters flooding the scene, blocking the road. Reporter at talked defrance where the National Team was match, more bombings. Loud explosions rocking the stadium. Stopping players in their tracks. French president Francois Hollande was at the game. Translator at first i thought it was a homemade bomb. There were rumors the stadium. It was going off next to entrance e. It was newsy. We heard rumors of a shooter. It was very confusing inside the stadium. The crowd started moving. Everyone started panicking. It was impossible to leave. Trains were blocked, people everywhere, its chaos in paris. Reporter thousands flooding the field. Confused by what happened. Amid the chaos, a moment of patriotism. Reporter fans singing Frances National anthem as they evacuated the stadium. Translator paris has paid a heavy price in the face of terrorism. But we are standing tall and we will stay standing tall. The death toll is very high. The sites targeted are sites where pa rings like to go out. Where young people in paris like to go at the weekends and in the evenings. Reporter tonight france under lockdown for the First Time Since world war ii. Residents ordered to stay home. All public buildings closed indefinitely. Checkpoints up at the borders. Translator france needs to be strong. The authority of the state firm. One of the keys is going to be as they identify these eight dead extremists, what circle are they from . Theyre going to pull all of their phone records, their social media backgrounds, all of that stuff to look at the possibility of who else is in their pool . Reporter a somber president obama offered support. Weve seen an outrageous civilians. Paris. Its an attack not just on the but this is an attack on all of humanity and the universal values that we share. We stand prepared and ready to provide whatever assistance the government and the people of france need to respond. Reporter French Police believe all eight tackers are involved are now dead, killed by police or from suicide belts. Possible accomplices and answers. For some perspective on the global terrorism threat, joining me, abcs chief investigative correspondent brian ross. Extremism. The big question on everyones mind is whos responsible . Absolutely. We dont know yet but we will know soon. With at least eight suspects dead, authorities now have dna, fingerprints, and faces to match against terror data bases in both france and the u. S. And that process is already beginning. So far it has all the hallmarks of an isis attack. Sympathizers in france or residents. Isis known for its sophisticated social media campaign. Is it isis, al qaeda . I know theres debate under way. Absolutely. In the last month or two isis followers have been calling for paris. Certainly what happened tonight at that concert hall was a slaughter, a massacre of young people out to see an american rock n roll band. Nothing that isis or al qaeda hates most of than a bunch of people out to have a good time going to a soccer game, going to a concert, out for a few drinks with friends. That was the target tonight, very soft targets. Decadent western culture. Thank you for your updates and insights. Coming up next on this special edition of nightline, what tonights tragic events in paris mean for Homeland Security and what counterterrorism experts are saying about the string of recent deadly terror attacks. Stay with us. M mary ellen, and i quit smoking with chantix. I was able to quit in three months. And that was amazing. Along with support, Chantix Varenicline is proven to help people quit smoking. It absolutely reduced my urge to smoke. Some people had changes in behavior, thinking or mood, hostility, agitation, depressed mood and suicidal thoughts or actions while taking or after stopping chantix. Some had seizures while taking chantix. If you have any of these, stop chantix and call your doctor right away. Tell your doctor about any history of Mental Health problems, which could get worse or of seizures. Dont take chantix if youve had a serious allergic or skin reaction to it. If you have these, stop chantix and call your doctor right away as some can be lifethreatening. 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Tonight u. S. Law enforcement officials are in a desperate hunt for clues to help the french figure out who is behind this nightmare. The two countries face common enemies. Islamic radicals targeting the western way of life. Tonight france feels only a short distance away from the u. S. Homeland. Law enforcement officials here worry that the attack may not be isolated and theyre stepping up security. Theres complete urgency in finding out who is behind this. The critical question tonight, who did it . On the short list of possibilities, al qaeda and isis. In part because of recent history. The tactics used in this specific attack are very similar to what we have seen in the past in attacks carried out by al its too early to tell for sure who conducted it now but it wouldnt surprise me at all if it was either an al qaeda affiliate or isis. Reporter just last january, there was a spree of terror in france. Two brothers forced their way into the office of the french satirical newspaper Charlie Hebdo in paris, killing 11 and injuring nearly a dozen more. In this video al qaeda in the Arabian Peninsula claimed responsibility for the assault and say one of the two terrorist brothers traveled to yemen to receive training and funding from the al qaeda affiliate there. Another gunman took several hostage in a supermarket near paris. Authorities found evidence in the gunmans apartment he was connected to isis. His partner fled france and is believed to have traveled to syria. Laictiond has been looking for ways to do a largescale attack for years. They most recently fixated on blowing up commercial airplanes since 9 11 when they conducted the most devastating attack in u. S. History. In recent months al qaeda has been working on a socalled undetectable bomb that could get past airport security. But perhaps the most active terror group on the planet right now is isis. Consuming huge swaths of land in iraq and syria. Forming the socalled islamic state. Thousands of foreign fighters flowing into those countries unprecedented. Recruiting people from around the world, including in the u. S. And europe. More than 1,500 french citizens affiliated with isis, onequarter of the european total. This past july, a frenchspeaking member of isis appeared in this video threatening the group will bring slaught tore france. There have been a relatively large number of individuals from france who have traveled to syria, joined with the groups in the conflict there, and then have come back home. Just as extreme or even more extreme than before they left. Reporter this new yorker Magazine Article described a region called department 93. A large area of disaffected african and arab populations who feel cut off from french society. According to the article, estimates are 60 of french Prison Inmates are muslim. Prime targets for jihadists. One of the challenges that the french government and the french people will face in the days ahead will be to ensure that hate crimes arent committed against people who had nothing to do with this attack. Thanks to pierre for tracking the moving parts in this fluid situation. Joining us former white house counterterrorism official and abc news consultant richard clarke. There are reports the Intelligence Community was not picking up any increased chatter leading up to the attack. What does that tell you . Intelligence Community Officials are worried tonight and they have two theories. The first is that the french intelligence people are just too overstretched, there are too many suspects for them to follow in detail and listen to all of their phone calls. The other theory is that isis, figured out ways to avoid western intelligence detection. They may be employing people who are not known to western intelligence. And that would be very troublesome. And youre beginning to see signs, a pattern, in fact, of recent attacks outside of syria, outside of the region . Isis has always just done attacks in iraq or syria. But over the last week weve had three major attacks that could be isis. First the russian airplane downed in egypt. Second, yesterday, the first major attack in beirut in years. One directed against isis foes, the Hezbollah Group backed by iran. And then this one today. It could well be that the external arm of isis, which we have known for a while exists, but have never seen them do anything, it could be that that arm has finally been activated and has executed three planned attacks all in one week. And on the heels of that coordinated attack, an attack in paris, six separate attacks does that suggest to you perhaps a new threat level . Its certainly a very complicated attack to pull off. It suggests the personnel involved in planning it and some of the people involved at least in executing it must have france. Most possibly in syria or iraq. To isis. But what that means for the United States is unclear because theres not a widespread group that isis can reside in here in the United States. The way this is in france where there are thousands of people with isis sympathies and hundreds of people who have gone to syria and iraq. And brian ross telling us that the forensic investigation is already well under way. What, if anything, might they learn from the investigation that might help stop the global well, im not sure the investigation will tell us anything about how to stop it. Except if we try to focus not on who the people were but why they were converted. Why were they converted to this fundamentalist view of islam . This violent view of islam. The only two ways that we can stop this threat in the long term are, one, by going after them in their headquarters in their homeland, and destroying their organization, destroying their leadership. But two, going after them ideologically, cutting off the roots, getting to have our arab friends do the work of convincing other arabs that this is not true islam, this is in fact what the muslims call haram, not religious, it is in fact a sin. Richard clarke, always grateful for your expertise. When we come back, powerful symbols of solidarity from across the globe. President obama and a chorus of World LeadersStanding Firm with paris after tonights deadly attacks. Welcome to the most social car weve ever designed. The 2015 nissan murano. Recipient of autopacifics bestinclass Vehicle Satisfaction award. Now get great deals on the nissan murano. vo whats your dog foods first ingredient . Corn . Wheat . In new purina one true instinct grain free, real chicken is always 1. No corn, wheat or soy. Support your active dogs whole body health with purina one. Think your heartburn pill works fast . Take the zantac it challenge zantac works in as little as 30 minutes. Nexium can take 24 hours. 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