Transcript for Embedding with US military leaders combating ISIS on Syrian border in Iraq: Part 1
After dark in Baghdad we board a blackhawk. 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 part 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. Remarkably almost the same fight plan. It really is. Very familiar flight plan. That's right. 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. Reporter: U.S. Strikes from the air and then the Iraqi forces sent in on the ground. Hidden in the desert is their operations center. They take us past the concrete barriers, where we find U.S. Troops and their eyes trained on ISIS. So welcome to anbar and task force Spartan. This is our combat operations center. Reporter: Where they reveal to us the ISIS fighters they have just targeted. You were telling me you've already seen enemy movement. We have. Reporter: 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 bed-down location and we were able to go ahead and conduct a strike on them. Because they don't have a territory anymore, they're literally trying to blend in with other Iraqis? In the desert sometimes they try to blend in, look like shepherds or just transiting through the area. In the cities they try to look like the citizens and the people of anbar so that they don't draw attention to themselves. Reporter: This strike just days before on an ISIS tunnel in mosul. That city controlled by ISIS not so long ago. And this strike at another ISIS hideout north of Baghdad where they were sleeping at night. Best way to describe them would be sleeper cells because they're there intentionally not to draw attention, live another day to fight. But you're fairly convinced you've got two ISIS fighters. If I was a betting man I'd put money on it. Reporter: At sunrise we are take tyne remote area not far from the command center where we're 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 shadow-like, watching the Iraqis as they drill. They storm this small space, not unlike the caves with corners they'll soon be sent into to flush out ISIS. The Iraqi commandos will be the front line against ISIS here. The fact that they're able to do this on their own speaks a lot to their capabilities. Those American drones, though, hovering up above, finding intelligence and when you share it with these Iraqi commandos on the front lines. It was pretty good that we were hearing that above because that's exactly right. Reporter: In the middle of the desert we are 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. Reporter: We are allowed inside. A rare view of what it is they see. The kind of terrain they're scouring. And we're about to see for ourselves what's playing out right now deep in the anbar desert, where ISIS fighters cross over the Syrian border into Iraq. As you can see, we are back up in the air again flying over the Iraqi desert. We are headed west of Ramadi. In 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. One of the Blackhawks landing just before us. We are -- we're at the western edge. Hopefully air field -- we're deep into the command area of operations. Reporter: This remote post in the outer reaches of the desert. I took note while we were flying out here you could hear the pilots talking about vehicles off in the distance, completely aware of every isolated scene on the way out. Just a reminder that ISIS is out there. Reporter: 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 of them, krarmted 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, lieutenant. Good to see you. Good to see you. They take us into this small tent where the general using his laser pointer shows us where they're hunting. Are you confident you'll be able to get rid of ISIS in Iraq? Yes. Reporter: And then the general offers this. They know the Iraqi forces are looking for them. They are looking for them deep here in the Iraqi desert. But 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 elhol, 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. Militaries leaders say, are the ISIS fighters who have disappeared into the crowd and in parts of the camp children now celebrate the ISIS flag. Reports of ISIS flags inside that camp? That's right. There's one section of the camp where most of the hardcore ideologues seem to be located. Raised an ISIS flag. Children were dancing around the flagpole. Clearly indoctrinated into that ideology. It's a legitimate concern that this is becoming a breeding ground. Absolutely. Reporter: At another refugee camp arisha we find so many smiling faces but among them the children we are told who are being radicalized. One of the camp managers says he fears what the future will bring because he says ISIS is inside now, stealing childhoods. They prevent them to go to school. There are some children who promise that out of the camp they will go maybe with ISIS. Reporter: U.S. Military leaders say it is impossible to know how many mothers have also been teaching their children how to hate. We see indoctrination of their children as well. So you can almost see the next generation of ISIS being brought up in that ideology. Right there in the camp? Right there in the camp. Absolutely. Reporter: 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. There are at least 10,000 of them. 2,000 have come from all over the world, including the U.S., and inside the prison ABC news was given rare access. Down the hallway the prison doors bolted. Inside the vast majority are ISIS fighters. Some proud to look straight into the lens. This fighter, Abdullah halem, 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 in released. So he can fight and kill Americans, he says, because they are killing us and we will kill them. Is there any question in your mind that they would take back territory if given the opportunity? Not at all. We know that's their plan. Right now. Absolutely. Reporter: And tonight this who will ultimately take these prisoners? There are reports up to 10,000 ISIS fighters are being held by american-backed forces right now. What do you do with those fighters? It's a really good question. And it's a tough question. We've got to get the countries to take ownership of their folks who came here into the battlefield, take them back and figure out how to bring them to justice. Reporter: And part of that means Americans who took up the fight with ISIS back home to face justice here. There were Americans among the fighters. That's right. And at least some of them have been sent home. Correct. Reporter: Tonight several Americans home already and charged. When we come back, the children r5dicalized. Brought up by parents, family members devoted to ISIS. You saw the ISIS flag, reports of the children dancing. In a moment, what they're doing right now for the children left behind by fighters who did not come home. Some of their parents surrendering. The ISIS children orphaned. What's being done to rehabilitate them, to free them of their ISIS ideology, and what the children reveal, what it was like. Life on the inside, when we come back.
This transcript has been automatically generated and may not be 100% accurate.