AMNA NAWAZ: After Russia attacked Ukraine in 2022, some 20,000 Ukrainian children were forcefully transferred to Russia.

That's according to war crimes charges filed in The Hague last year that named President Vladimir Putin and an aide as the prime culprits.

GEOFF BENNETT: So, as the city of Mariupol in Southern Ukraine was being surrounded by Russian troops, the head of a Christian orphanage decided to take matters into his own hands to get 19 children to safety.

With support from the Pulitzer Center, special correspondent Simon Ostrovsky has this report.

SIMON OSTROVSKY: This is Gennadiy Mokhnenko, an evangelical pastor from Mariupol.

He runs a charity called the Chaplains Battalion staffed by evangelical ministers who were forced from their churches by Russian soldiers.

Before the war, Pastor Gennadiy ministry involved helping the homeless children from the streets of Mariupol, but now his job is bringing aid to soldiers and civilians along the front line.

"NewsHour" met the pastor in the southern Zaporizhzhia region, where danger from the sky is a constant threat to his humanitarian work.

MAN (through translator): Do you hear that buzz?

It flew near us, then over the road.

MAN (through translator): Please stay in the kitchen.

SIMON OSTROVSKY: They have just noticed a drone up in the sky, a Russian suicide drone, so the soldiers here have asked us to stay inside so it doesn't see us.

GENNADIY MOKHNENKO, Chaplains Battalion (through translator): This is the perfect moment for a chaplain's prayer.

Please lord, protect us from these enemy drones and make them fly away from here.

Bless these men, in the name of the father, the son and the Holy Spirit.

SIMON OSTROVSKY: Before the war, Pastor Gennadiy was a respected figure in both Ukraine and Russia, as evidenced by this documentary celebrating his work with street children made by state-owned broadcaster Russia Today in 2013.

GENNADIY MOKHNENKO (through translator): We tried to clothe them, bathe them.

They were completely flea-ridden.

That's how the Pilgrim republic got started right here.

SIMON OSTROVSKY: But when Russia launched its war against Ukraine, he went from hero to villain overnight.

Here's the Russian ambassador to the U.N. describing Pastor Gennadiy's home for children as a secret military training camp.

VASSILY NEBENZIA, Russian Ambassador to the United Nations (through translator): In a number of regions in Ukraine, to this end, they have set up children's camps where children from seven to 18 years old are hosted.

One of these camps was the Pilgrim camp in Mariupol, where children were turned into future fighters.

SIMON OSTROVSKY: The vilification of Pastor Gennadiy's organization is no coincidence.

Since its invasion, Russia's propaganda machine has systematically sought to characterize evangelical Christians across occupied Ukraine as extremists or charlatans to justify the seizure of their property and the erasure of their religious communities.

MAN (through translator): All kinds of cults and pseudo-religious sects have sprung up in Ukraine.

The activities of these swindlers in Russia's new regions has been curtailed considerably since the start of the special military operation.

GENNADIY MOKHNENKO: When we evacuated my orphanage from Mariupol, it was like competition between my convoy with children and Russian tanks.

Ukrainian soldiers called me and said: "Pastor, you have just 40 minutes, last 40 minutes, not 45, not 50.

It's last chance."

It's crazy.

SIMON OSTROVSKY: Once Pastor Gennadiy and his orphans were out of Mariupol, there was no way back.

Russia and Ukraine established an impenetrable front line.

His church was eventually gutted in the fighting.

GENNADIY MOKHNENKO: Inside many holes of the Russian mortars.

Later, Russia rebuilt this building, and they used it.

SIMON OSTROVSKY: This is his church today.

Russia expropriated the building and turned it into a municipal service center.

Some 206 evangelical and Protestant churches have been expropriated or destroyed in an effort to bolster Russia's Orthodox Church through force.

Meanwhile, Gennadiy's life work, the Pilgrim Orphanage, was converted into a military barracks.

But Pastor Gennadiy says he lost a lot more than the physical property.

One of his 36 adopted children was killed.

GENNADIY MOKHNENKO: They killed my daughter.

They killed many of my friends.

They killed many of my church members.

Russian soldiers sleep inside my children's bedrooms.

We pay huge price now for freedom.

SIMON OSTROVSKY: Oleksandr Zaiets is the chairman of the Institute for Religious Freedom, a Ukrainian watchdog group.

He told "NewsHour" Russia is killed As many as 40 religious leaders in the course of the war.

At least 45 have been detained or imprisoned by Russian forces, the majority of whom are evangelical pastors.

At least seven are still being held.

OLEKSANDR ZAIETS, Chairman, Institute for Religious Freedom (through translator): Many prayer houses have been closed, sealed off, and believers are forced to gather in private homes in secret in order to pray and take part in rituals.

The occupation forces in the occupied areas are of the opinion that they are all American spies or secret agents for the West.

SIMON OSTROVSKY: Dmitry Bodyu is one of the many pastors Russian forces kidnapped and accused of being an American spy.

DMITRY BODYU, Word of Life Church: They just came early in the morning to our house, about 15 guys fully loaded, like machine guns, shields and everything.

And I was arrested.

They took me to church.

They searched house, church and everything.

They took me to prison.

SIMON OSTROVSKY: Pastor Dmitry is an American citizen originally from Ukraine.

After being ordained in Texas, he founded the Word of Life Church in the southern Ukrainian city of Melitopol.

DMITRY BODYU: They accused me that I was running this underground operation in Melitopol.

All the protesters and everything was under my command.

We were supporting the Ukrainian army with finances and weapons and things like that.

So... SIMON OSTROVSKY: Was any of that true?

DMITRY BODYU: No.

SIMON OSTROVSKY: Do you think part of the reason that they arrested you and took you captive was because you're an evangelist?

DMITRY BODYU: They were telling this.

They said: "We hate three kind of people, Americans, Nazis and evangelicals.

You're all three."

And they said: "We have a command to kill you."

So the way they said, like, "You have a one-way ticket."

SIMON OSTROVSKY: Pastor Dmitry spent four more days in solitary confinement waiting to be executed.

Instead, he was released without explanation.

He's since fled Melitopol, but continues to minister in areas that have held out against Russia.

Russia, in the meantime, repurposed his church.

DMITRY BODYU: Now it's a police department.

So there's a police department.

They do all kinds of things in there and they cut down cross.

They really hate evangelical churches.

SIMON OSTROVSKY: And yet people say that Vladimir Putin is a Christian, family values, conservative leader.

DMITRY BODYU: No.

He divorced his wife.

Where is the family?

GENNADIY MOKHNENKO: What I hear, oh, Putin, he's pro-family, pro-Christian guy.

Are you serious?

I'm very angry.

I don't understand this.

This is fighting about freedom, especially religion freedom.

SIMON OSTROVSKY: Two years have passed since Pastor Gennadiy escaped Mariupol with the orphans from his rehabilitation center.

They spent most of that time in Germany.

But now, finally, they're ready to come home.

He becomes emotional as he drives to the Polish border to meet them.

Pastor Gennadiy says he never expected to survive long enough to see them again.

GENNADIY MOKHNENKO (through translator): How's it going?

MAN (through translator): We're at the border, Pastor.

We're transporting the luggage and the kids are crossing by foot.

(LAUGHTER) SIMON OSTROVSKY: Although Pastor Gennadiy's orphans have returned to Ukraine, Western Ukraine for now, he still prays for the day when they will be able to go back to their hometown of Mariupol.

For the "PBS NewsHour," I'm Simon Ostrovsky in Zaporizhzhia, Ukraine.