Transcript for Exclusive: David Muir goes inside Iraq as US hunts ISIS fighters
We turn next tonight to an ABC news exclusive. The hunt for ISIS fighters. Tonight, we take you deep inside Iraq, after the president celebrated the defeat of ISIS, their territory taken back, where they are now. Tonight, we're with U.S. Forces as they hunt for ISIS. And this evening, our exclusive access inside Syria, the refugee camp where the children are dancing around the ISIS flag. And the prison where ISIS fighters are determined to fight again. After dark in Baghdad, we board a black hawk. U.S. Forces giving us exclusive access to an assault under way right now. As the U.S. And Iraqis hunt down ISIS fighters. We are flying out over Baghdad right now after nightfall, all partal of an operation to capture ISIS fighters, intelligence shared between the Americans here on the ground and the Iraqi fighters. We're going to be landing between Fallujah and Ramadi. This operation now under way. They take us west of Baghdad to a base where they hunt them down from above first. 24 hours a day, surveillance in the sky, looking for ISIS fighters now hiding in the desert, the mountains, the caves of Iraq. And in the villages, ISIS fighters trying to blend into the population. You find yourself back in anbar province to catch ISIS fighters. Yeah. We sure do. Did you ever think that would happen? I did not. It's a very surreal experience to be back here in anbar, 14 years later from doing offensive operations out here against Al Qaeda in Iraq. We drive to the command center where we learn there has just been a strike on ISIS fighters. Has it been lucrative? It's been successful. Hidden in the desert is their operation center. They take us past the concrete barriers where we find U.S. Troops and their eyes trained on ISIS. So, welcome to task force Spartan. This is our combat operation center. Where they reveal to us the ISIS fighters they have just targeted. You were telling me you've seen enemy movement? We have. And tonight, ABC news obtaining these images of that strike. They tell us two ISIS fighters were spotted where they were sleeping. Not far from where they were keeping their weapons. This is where they retreated to. We found them because they got up and moved. They went over to another location to pull some weapons out. When they went back into their beddown location, we were able to go ahead and conduct a strike on them. This strike, just days before on an ISIS tunnel in motional. That city controlled by ISIS not so long ago. And this strike on another ISIS hideout north of Baghdad where they were sleeping at night. The best way to describe it would be sleeper cells, because they're there intentionally, trying not to draw attention, you know, live another day to You're fairly convinced you have two ISIS fighters? If I was a betting man, I'd put money on it. At sunrise, we are taken to a remote area not far from the command center, where we are told helicopters will soon drop off Iraqi commandos being trained by U.S. Forces. They land, American troops vanishing in the desert sand. These U.S. Forces are shadowing, watching the Iraqis as they drill. They storm this small space, not unlike the cave us, the corners they'll soon be sent into, to flush out ISIS. These Iraqi commandos will be at the front line against ISIS here. The fact that they're able to do this on their own speaks a lot to their capabilities. In the middle of the desert, we're shown the unmanned drones. They are guarded, fueled and ready for flight. In the skies over Iraq eight hours at a time. This is where they're actually operating the drones that are doing surveillance right now over the Iraqi desert. The mountains and the caves where they believe these ISIS fighters are still hiding. You can see this private first class is looking at some terrain right now. We are allowed inside, a rare view of what it is they see. The kind of terrain they're scouring. And we are about to see for ourselves what's playing out right now, deep in the anbar desert, where ISIS fighters cross over the Syria border into as you can see, we are back up in the air again, flying over the Iraqi desert. We are headed west of Ramadi, deep into the anbar desert to find a command center for this operation under way right now to capture ISIS fighters. Our flight over the desert in 115-degree heat. We hear the pilots pointing out every lone vehicle, every lone person they see on the horizon. They are ready. And then we see it. The small command post just 50 miles from the Syrian border. We are very far western edge of Al anbar desert. This post in the outer reaches of the decemberer. You could hear the pilots talking about vehicles off in the distance, completely aware of really every isolated scene on the way out. Yeah. Just a reminder that this is -- ISIS is still out there. As we arrive, we learn an ISIS fighter has blown himself up, killing another ISIS fighter in the process. The Iraqis then moving in, capturing five more ISIS fighters at that location. We have blurred the Iraqi translator for his safety. This is where the operation is under way right now deep in the anbar desert, about 50 to 60 miles from the Syrian border. You can see the Iraqi troops behind me and the tribal militia setting up this defensive perimeter. They are here to find these ISIS fighters. They've captured another seven or them, captured and killed here in the search for these fighters. The new reality -- this is where the ISIS fighters are hiding. The Iraqi general is waiting for us. Hello. Good to see you. They take us into this small opportunity, where the general, using his laser pointer, shows us where they're fighting. Are you confident you'll be able to get rid of ISIS in Iraq? Yes. Right across the border in Syria, ABC news is shown the other major threat. Senior U.S. Military leaders telling me this refugee camp is one of their greatest concerns. Inside it, tents as far as the eye can see. Children sitting in the open air. Mattresses on the back of pickups. The young refugees looking out. But what you don't see, U.S. Military leaders say, are the ISIS fighters who have disappeared into the crowd. And in parts of the camp, children now celebrate the ISIS flag. ISIS flags inside that camp? That's right. There's one section of the camp where most of the hard core ideology logs seem to be located. Raised an ISIS flag. This is a legitimate concern. Absolutely. And our team is taken to one last place. One of the prisons just across the border in Syria. Where the american-backed forces are holding those prisoners. And inside the prison, ABC news is given rare access. Down the hallway, the prison doors bolted. Inside, the vast majority are ISIS fighters. This fighter says he was a security officer for ISIS for a year. He worked with explosives and targeted police stations. And he tells us he will rejoin ISIS if released. So, he can fight and kill Americans, he says, because they are killing us and we will kill them. And on the other side of the border, in Iraq, we fly back to Baghdad and we witness what the U.S. Military already knows. That this is a fight far from over. And many of these military leaders have been to Iraq before. Came back again for the ISIS fight. I'm curious. Six tours later, did you think we'd be heading out to anbar to get the enemy again? It is -- it is surreal that we're going back out to Al that's where they are. But that's where they'll die. And you saw that prison there. There are at least 10,000 ISIS fighters in custody of u.s.-backed forces in Syria right now. About 2,000 of them from countries all over the world, including the U.S. Tonight, we've learned so far, at least eight American adults and 13 children have been brought back to the U.S. And tonight, on "Nightline," our exclusive reporting continues with the children. Radicalized by ISIS and the rehab center where they are trying to free the children from ISIS ideology. That's later tonight on a special edition of "Nightline."
This transcript has been automatically generated and may not be 100% accurate.