Transcript for Manhunt Underway After Shooting Attack at Istanbul Nightclub

Good evening from a cold and blustery it's done bull the biggest city in Turkey we are on the banks of the Bosporus strait which you can't Ciba which is right there dividing. The continents of Europe and Asia and right behind me in the distance there. You can see the re not club that was the site of the massacre. On New Year's Eve that left 39. People dead more details are coming out in the wake of that horrible attack. The single attacker the shooter who. Took so many lives has still not yet been apprehended there is a massive manhunt under way here in Istanbul and beyond. To find. That suspect he. Believe we believe he is a young of mailed the Turkish authorities have been putting out pictures and video of him. In their efforts to try to find him let me break you down. For how it happened it was the night of New Year's Eve. The clock struck midnight and just like parties all around the world people counted down with sparklers with confetti. Ringing in the new year. At 115. In the morning a gunman came down to street starting to fire an automatic weapon he killed. At least one maybe more people outside a club before storming into the club. All of this took just seven minutes in those seven horrifying minutes he managed to kill 39 people. And injure. Dozens of them there are still several who are in critical condition we have been learning the nationalities of those who were killed the vast majority. Were from foreign countries many from Arab Muslim countries around eleven of them were from Turkey itself we've seen some of those funerals taking place. Since this horrific attack. And in the days. That fallout now. This morning Dave biggest development that we heard was that vices has claimed responsibility for this attack they were the immediate suspects. Behind this attack it's unclear whether. Ices directed. This young man this suspects. Or whether he was simply inspired by them this morning ice is putting out a statement. Saying. That's the reasons essentially for carrying out the set attack were twofold first of all. That Turkey has who is working alongside BI US led coalition against ices in Iraq and Syria Turkey. Has been firing artillery carrying out airstrikes against ice is positions. For several months now and in the last few days against ices positions in Iraq and Syria and the second reason. That they said this attack was carried out was because. This club the rain up. Was hosting what they called Christians celebrating an apostate holiday. That Boston holiday meet a reference to New Year's Eve this sad irony. Is that. The vast majority of those killed. In this club were in fact Muslims and that holds true for. The vast majority of licenses victims. They are. The vast majority are Sunni Muslims just like. The group themselves. Now this is this claim of responsibility is hugely significant because. We have seen attacks attributed diocese here in Turkey before. But never really claimed you might remember that attack against the assemble airport. Last year and claimed 44 lives that was instantly blamed. Nicest there have been others that aura blamed on ice this crisis has never claimed responsibility. Turkey is in the unique position in that they are the main conduit for crisis. Use send its fighters its weapons its money. Into Iraq and Syria and what do from their birth. Turkey was relatively lenient allowing these jihadist to cross the border into Iraq and Syria. Mainly to Syria. To fight against the S solders team but then to some extent you could say the chicken started coming home to roost. Turkey started cracking down. On the militant group and we started to seat the ice this response and that's what we're seeing now. After a very violent. Year in 2016 with a number of attacks that were attributed diocese. There were hopes perhaps. That this would be a home or year but right out of the gate. On January 1 in the first hours of the first day of the new year this horrific massacre taking place. Which. It's a sign that. Which doesn't bode well for the new year possibly a signal that there will be much more this here in Turkey and beyond in the west. In a stumble on Alex Marquardt for ABC news.

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