♪ ♪ >> NARRATOR: Tonight, two stories from a war-torn region.

>> Iraq's prime minister declared victory over ISIS in Mosul.

>> NARRATOR: A nine-month fight to save a city.

(rapid gunfire) (firing) Street by street with Iraqi special forces... (gunfire and yelling) ...as they drove out ISIS... (gunshot and explosion) ...and liberated Mosul.

And later tonight, a reporter's journey through a country rarely seen by foreign journalists.

>> (crying) >> NARRATOR: Correspondent Martin Smith's firsthand account of the toll of war and disease "Inside Yemen."

>> (imitates jet streaking) Boom.

>> NARRATOR: Two gripping stories on this special edition of "Frontline."

♪ ♪ >> Tonight's program contains mature content, which may not be suitable for all audiences.

Viewer discretion is advised.

(speaking foreign language): (distant rapid gunfire) (distant gunfire continues) (gunfire) (speaking foreign language): (loud gunshot) (gunshots, debris falling) (glass breaking) (glass crunching) (distant rapid gunfire) (clicking tongue) (distant shouting) (distant rapid gunfire) (gunshot) (rapid gunfire) (loud explosion, debris falling) (man shouting) (rapid gunfire) (man gasping) (radio chatter) (man gasping) (brakes squealing, men talking) >> 13 years after the U.S. military invasion, the country still faces profound challenges, none more dire than the threat posed by the Islamic State.

(radio chatter) >> The capture of Mosul in June 2014 shocked the world and became a symbol of the emerging threat of the so-called Islamic State group.

>> There are over a million civilians in Mosul.

ISIS is not letting them leave.

It's using them as human shields.

>> They're describing a life of torture under the Islamic State's brutal rule.

>> The Iraqi prime minister has announced just moments ago the offensive to take back Mosul is now underway.

>> ISIS recognizes that there is a big battle ahead for Mosul, Iraq's second-largest city.

>> This is the place where I.S.

proclaimed its caliphate.

Here it was born, and here, Iraqi forces say, it will die.

(speaking foreign language) (gunshots) (men shouting) (distant rapid gunfire) (distant gunshot) (gunfire, explosion) (rapid gunfire) ANMAR: (gunshots) JAMAL: (speaking foreign language) (explosions, gunfire) HUSSEIN: (distant gunfire) (loud explosion) (gunfire, explosion) (rapid gunfire) (rapid gunfire) (rapid gunfire) (gunfire) ANMAR: (explosion) (firing, rapid gunfire) (voice trembling): (baby crying) (car horn beeping) ANMAR: (hissing) (explosion) >> Whoa!

(dog barking) BOY (on radio): MAN (on radio): BOY: MAN: ♪ ♪ ♪ ♪ (engine stops) HUSSEIN: (gunshot) (distant gunfire) (radio chatter) ANMAR: (distant gunfire, men shouting) (gunshots) (men shouting) (loud gunfire) (gunshots) HUSSEIN: (men shouting) (water bubbling) >> Hello?

(water bubbling) ♪ ♪ (indistinct chatter) ♪ ♪ (laughter) ♪ ♪ JAMAL: (distant gunfire) (distant rapid gunfire) JAMAL: (radio chatter) (distant rapid gunfire) (distant rapid gunfire) (loud rapid gunfire) (loud gunfire continues) (firing stops) HUSSEIN: (distant gunfire) (laughter) (nearby gunshot) (chuckles) (dance music playing) (music continues) (distant rapid gunfire) (metal clanging) ♪ ♪ JAMAL: (men shouting on phone) (rapid gunfire on phone) (sheep bleating) (men shouting) ♪ ♪ ♪ ♪ ANMAR: (people talking) (people talking) (radio chatter) ♪ ♪ (men talking) ♪ ♪ (indistinct chatter) (indistinct chatter) ANMAR: (indistinct chatter) (door thudding, clanging) (fires) (distant explosions) (loud gunshot) BOY: QASSIM: QASSIM: QASSIM: QASSIM: QASSIM: QASSIM: QASSIM: ANMAR: ANMAR: (distant rapid gunfire) (explosion) (distant gunfire) ♪ ♪ MAN (on radio): (radio chatter) (weeping) (continues weeping) (men talking, distant gunshot) HUSSEIN: (distant gunshots) (sniffles) (indistinct chatter) (lighter clicks) (aircraft flying overhead) (metal clinking) (bullets clanging) (man shouting in the distance) ANMAR: (music playing softly) (men chatting) (distant gunfire) (man shouting) (distant gunfire) (gunfire continues, man yelling) MAN (on radio): (explosion roars) (explosion roars) (gunfire in distance) (water bubbling) ANMAR: (faint explosion, gunfire) ♪ ♪ (explosion) ANMAR: (explosions) (rapid gunshots) (rapid gunfire) (distant gunshots) WOMAN: SOLDIER: (distant gunshots) MAN (on radio): (distant rapid gunfire) (gunfire stops) (firing) (distant gunfire) HUSSEIN: (meowing) JAMAL: (distant gunshots) ♪ ♪ (rapid gunfire) (firing) (rapid gunfire echoes) ♪ ♪ ♪ ♪ HUSSEIN: (explosions, gunfire) (rapid gunshots) (fires) (men cheering) (singing, clapping): ♪ ♪ (crickets chirping) JAMAL: ♪ ♪ ♪ ♪ ♪ ♪ >> NARRATOR: Up next, correspondent Martin Smith was one of the few journalists allowed into Yemen.

>> You were standing right here.

>> NARRATOR: His firsthand reflections on the rarely seen consequences of the country's devastating war.

>> They were there working in spite of the fact that they hadn't been paid.

>> If I will not work, then they will die.

And maybe tomorrow, I will be sick, and nobody will see me because of no salary.

>> NARRATOR: "Inside Yemen" begins right now.

♪ ♪ >> SMITH: When we were in Yemen in May of 2017, we were the only foreign journalists that were able to get permission to enter the country.

We wanted to come in and see the consequences of two-plus years of war and airstrikes by a Saudi-led coalition.

You have the region's wealthiest country bombing the region's poorest.

And people are not seeing what's going on.

We're talking thousands of civilian dead.

BOY (speaking Arabic): (imitates jet streaking) Boom.

(imitates jet streaking) (music playing on radio) >> SMITH: The current war began when the Houthis, a rebel group from northern Yemen, took the capital in 2014.

Months later, the Saudis responded with a massive air campaign.

(camera clicking) And there's a lot of blame to go around here.

The Houthis have blocked aid shipments, they've detained and even tortured their opponents, and they've prevented human rights organizations from doing their work.

But nothing has really caused as much death and destruction as the Saudi bombs.

We went to the site of a funeral bombing.

It had taken place late last year.

And the Saudis say they mistook it for a gathering of Houthi officials.

You were standing right here?

(man speaking Arabic) >> He was the last... >> SMITH: It was what's called a "double tap."

As people ran back inside to save lives, a second missile hit.

About 150 people died there.

400 to 500 people were injured.

This man says he lost 26 members of his family.

The Saudis say this was a mistake.

That they didn't intend to bomb a funeral.

>> SMITH: We were taken to other bombing sites by our Houthi minders, but the fact is, you can see the war in Yemen wherever you go.

It's just not always immediately evident.

We were in one supermarket in the capital, Sanaa, and it was a fairly well-stocked supermarket.

It looked like a lot of supermarkets in the U.S. We then noticed that people were paying not with cash, but with coupons.

>> SMITH: We ran into people who were working and hadn't been paid in many, many months.

The whole banking system had pretty much collapsed, so the cash just wasn't there.

That's just a small example of how you see the war affecting people's daily lives everywhere you go.

It's not just the jets you hear overhead or the buildings that are bombed or the airport that's demolished.

It's the knock-on effects of the war on infrastructure.

When we came into town, what struck me right away was the amount of garbage on the streets.

The garbage workers hadn't been paid in eight months.

The rains came, washing through the garbage.

Bacteria carried into the water supply.

People drinking bad water.

And they were hit by a cholera epidemic.

(chattering) Cholera simply dehydrates you quickly, so that anything you ingest-- any water you drink or food you eat-- just completely passes through your system and you get no nutrients out of it.

(woman speaking Arabic) >> WOMAN (speaking English): >> SMITH: The World Health Organization is saying that they expect more than 700,000 cases of cholera, and that 2,100 people have died.

Most of those are children.

The hospital we visited, they were already beyond capacity.

The nurses and doctors were suffering from a lack of medicines and equipment.

And they were there working in spite of the fact that they hadn't been paid.

>> WOMAN (speaking English): ♪ ♪ >> SMITH: People often ask why the Saudis are bombing Yemen.

It's a question for the Saudis.

They'll tell you that the Houthis are a proxy of their archrival, Iran.

And the Houthis are getting some Iranian support and training, but the extent is unclear.

And certainly they lack the firepower of the Saudis.

Parts of the country have been isolated because of bomb strikes on bridges.

People on the ground in Yemen are suffering.

They're caught in the crossfire of this war.

In Hajjah, we went to a hospital, and I met a nurse there who showed me pictures she'd taken a day or two before of a young boy who came in severely malnourished, and died.

WOMAN (speaking Arabic): (baby wailing in background) >> SMITH: She then was called away to go take care of a new severe malnutrition patient.

(baby crying) A mother came in with her child.

It was a little girl named Aaleen, a seven-month-old baby.

>> (crying) WOMAN (speaking Arabic): WOMAN 2: >> SMITH: There were always malnutrition cases in Yemen, but the nurse told us that the number of cases had more than doubled since the war.

Then maybe an hour later, another mother came in with her daughter.

Ruqayyah, her name was, was a five-year-old girl.

Ruqayyah had come from an IDP, an internally displaced persons' camp, that was quite a ways away, up near the Saudi border.

Traveled several hours because the hospital up near her had been bombed.

>> WOMAN (speaking Arabic): >> (crying) WOMAN (speaking Arabic): >> SMITH: And who do you blame for the war?

WOMAN (speaking Arabic): >> SMITH: We had to leave the hospital before I knew what the fate of those two girls was going to be.

I don't know what happened to them.

What I do know is that health workers in Yemen say that every ten minutes, a child dies of preventable causes.

(car horns honking) Americans may not be aware of American involvement in the war in Yemen.

But Yemenis in Sanaa and in northern Yemen certainly know where the weapons are coming from.

Just a few days after we arrived, there was a huge rally in the middle of Sanaa called the "Say No to American Terrorism" rally.

Thousands gathered to protest the arrival of President Trump in Riyadh, where he announced his intention to approve a $110 billion arms package to the Saudis.

>> We respect the United States of America, and we hold respect in our hearts.

But we came here in order to express our outrage against the United States policy.

(chanting in Arabic): >> SMITH: It was pretty evident that we were an American TV crew, but absolutely no hostility was directed at us.

There was only a sense that our government was to blame and ordinary Yemenis want the world to be aware of what's going on.

♪ ♪ >> There's this grievance that's eating away at Vladimir Putin.

>> The FBI detected more attempts to hack... >> Russian hackers are behind those attacks... >> NARRATOR: America in the crosshairs.

>> This is the first time they have gone out and weaponized that information.

>> He's going to employ whatever means he can to undermine the United States.

>> NARRATOR: In a two-night special investigation, the epic inside story of "Putin's Revenge."

>> Go to pbs.org/frontline for an interview with Mosul filmmaker, Olivier Sarbil.

>> Then, listen to the Frontline Dispatch, our new podcast series.

>> We're going to be tackling the toughest subjects.

>> I was caught in a car bomb in Mosul.

>> The thought of marriage at 14... >> Subscribe now at pbs.org/frontline.

♪ ♪ ♪ ♪ >> For more on this and other "Frontlne" programs, visit our website at pbs.org/frontline.

"Frontline's" "Mosul" is available on DVD.

To order, visit shopPBS.org or call 1-800-PLAY-PBS.

"Frontline" is also available for download on iTunes.

♪ ♪