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The Iraqi and U.S. militaries are stepping up operations in Iraq against ISIS. Yes, the militants were driven out of Iraq's cities a year ago and were largely defeated. But since then, some have dug into remote areas in the mountains. NPR's Jane Arraf went out with Iraqi forces in northern Iraq.
(SOUNDBITE OF DRONE BEEPING)
JANE ARRAF, BYLINE: An Iraqi army officer has just launched a drone. They're looking for ISIS fighters here in the Badush mountains in northern Iraq. The mountains are dotted with dozens of man-made tunnels. A lot of them are more than 300 feet long and as wide as a house. The military says ISIS sleeper cells are there.
GENERAL RASHEED ABID RASHEED: (Foreign language spoken).
ARRAF: General Rasheed Abid Rasheed is standing on a ridge briefing the commanding general, Nijm al Jabouri, on what his troops are doing.
RASHEED: (Through interpreter) We demolished most of the tunnels, but some, after we destroy them, they open them up again.
(SOUNDBITE OF DOGS BARKING)
ARRAF: Just down the mountain, there are sheep grazing on the grass. Dogs bark at the passing military convoy. It looks idyllic here, but a lot of ISIS members came from the villages around here. And a few days ago, an Iraqi soldier was killed by an ISIS fighter in one of the tunnels they're trying to destroy.
KATHIM ABID ZAID: (Foreign language spoken).
ARRAF: At the entrance to a tunnel, an army explosives expert, Kathim Abid Zaid, lays out explosives and a detonating cap. And then he pulls out a lighter. When everyone is at a safe distance, he lights it. But when it's done, the opening of the tunnel's only partially blocked.
ARRAF: So the soldiers carry tires up to the mouth of the tunnel, pour gasoline on them and set them on fire to mark the location. General Jabouri tells us he's requested an airstrike from U.S. forces.
GENERAL NIJM AL JABOURI: I think at 11:00, the Apache will come to support us. Now, F-16 in the sky.
ARRAF: Jabouri is in charge of security in and around Mosul. ISIS held the city for three years and declared it the capital of its caliphate. The fight to liberate it took nine months and killed thousands of soldiers and civilians. Jabouri, switching to Arabic, says they will never let ISIS back in.
AL JABOURI: (Through interpreter) We liberated Mosul with the blood of the martyrs and a lot of sacrifice. We will never give it up again.
ARRAF: The Iraqi military and its U.S. and coalition partners are focusing on getting rid of ISIS in the mountains of northern Iraq and the desert near Syria so they can't threaten cities again.
(SOUNDBITE OF WIND RUSHING)
ARRAF: We're on a windy mountaintop in between Mosul and the city of Badush, and there are American Apache helicopters circling overhead.
ISIS has made a comeback in the mountains and along the border, where Iraqi forces have recently sent thousands of soldiers. An entire division - more than 10,000 soldiers - are deployed now near the Syrian border, along with the militias that are part of Iraqi security forces.
UNIDENTIFIED OFFICER: (Foreign language spoken).
ARRAF: An Iraqi officer calls in coordinates for an airstrike.
(SOUNDBITE OF BOMBS EXPLODING)
ARRAF: A little later, the airstrike hits and smoke rises from the ridge near the entrance to the tunnels. And then we climb into a truck with a couple of Iraqi military intelligence officers.
(SOUNDBITE OF MUSIC)
UNIDENTIFIED MUSICAL ARTIST: (Singing in foreign language).
ARRAF: They turn up a song praising their militia partners. It goes, we're Iraqi. We're here to stay.
ISIS has been driven out of the cities, but the battle isn't quite over yet. Jane Arraf, NPR News, in the Badush mountains in Iraq.
(SOUNDBITE OF MUSIC)
UNIDENTIFIED MUSICAL ARTIST: (Singing in foreign language). Transcript provided by NPR, Copyright NPR.