After the latest of his sermons denouncing the Islamic State, Mohamed Taha Sabri stepped down from an ornate platform at the House of Peace mosque. The 48-year-old chief preacher then moved to greet his congregation, steeling himself for the fallout.

Soon, two young men — they are almost always young, but not always men — were calling him out. Only moments before, Sabri had derided the militants’ tactics, saying “it is not our task to turn women into slaves, to bomb churches, to slaughter people in front of cameras while shouting ‘God is great!’ ”

One young man in a black leather jacket angrily chided him for challenging “Muslim freedom fighters.” His companion in a yellow shirt then chimed in: “What is your problem with the Islamic State? You are on the wrong path!”

“No,” said Sabri, embracing the surprised young men. “My brothers, you are the ones on the wrong path.”

In the era of the Islamic State, the wrong path has become all too familiar ground at the House of Peace. Nestled between the kebab restaurants and bric-a-brac shops of an immigrant neighborhood in south Berlin, the liberal mosque stood for years as a temple of tolerance where battered Muslim women could find help divorcing their husbands and progressive imams preached a positive message of religious tolerance.

Roughly 16 worshipers have stopped attending prayer services in protest of Sabri’s stance. (Mario Wezel/For the Washington Post)

But as a ruthless brand of Islamic ideology radiates from the battlefields of the Middle East, the House of Peace has become a microcosm of the new fault lines developing inside countless mosques in the West. It illustrates the daily battle being fought against the militant group’s message by thousands of moderate religious leaders in Europe and beyond.

It is a fight that is sowing fresh divisions, and one the moderates do not always win. At least two youths who used to worship at the House of Peace — including Denis Cuspert, a former German rapper recently filmed holding the head of an enemy in an Islamic State video — have already left to wage jihad in Syria and Iraq. Another former worshiper here — an 18-year-old female convert to Islam — is now actively making plans to travel to Syria with an Islamic State fighter.

Roughly 16 worshipers have stopped attending prayer services in protest of Sabri’s stance. Two others were banned from the mosque for spreading radical views. Surveillance cameras have been installed and unauthorized gatherings prohibited to thwart radical recruiters. One burly 20-year-old worshiper became so enraged with Sabri’s Friday sermons against the Islamic State that he twice assaulted the slight preacher, once leaving him bleeding on the floor in need of emergency medical treatment.

“The Islamic State. It is like an invisible arm, coming to poison the wells where our children drink,” Sabri said. “We are losing something precious. We are losing our young people.”

Leaving for the caliphate

Three weeks ago, Imam Ferid Heider, a part-time preacher and coordinator of a youth group at the House of Peace, received an anonymous note asking if it is okay to kill Christians and Jews. Not long afterward, the author of that note — an 18-year-old girl who gave her name as Meryam — was wandering down a Berlin street with a journalist.

She wore a full Islamic covering known as a niqab, with only her green irises and pale skin visible through an eye slit. Even in a heavily Muslim neighborhood, she attracted the attention of passersby. “Let them watch, I’m used to it,” she said dismissively. “I don't care.”

Meryam is making plans to move to Syria with a Tunisian-born fighter for the Islamic State. A friend of hers has told leaders at the House of Peace of her intentions, but so far, the friend has honored Meryam’s request not to reveal her identity to the mosque, whose leaders still hope to stage a family intervention that might prevent her flight.

Members of the congregation of the mosque Neukoellner Begegnungsstaette pray outside, in front of the mosque, next to a small shop. Around 600 people attend friday prayer every week. (Mario Wezel/For The Washington Post)

Meryam agreed to tell her story to The Washington Post at the friend’s urging on grounds that her name be changed and that her real identity not be revealed to the mosque or German authorities.

She has a friend, she said, an Afghani girl, who has already traveled to Syria where she is living in a house with other single women waiting to marry a fighter. From that friend’s reports, the caliphate is an Islamic utopia, a place wholly different than the “lies” in the Western media that tell of repression and fear.

“It is our duty to leave the land of the unbeliever, to go and live in the caliphate,” she said.

Her awareness of the Islamic State has grown in recent months, she said. She has watched their videos on YouTube. Though she turns away from the ones with graphic beheadings and mass executions, she calls those acts righteous vengeance against nonbelievers.

Meryam is jobless. She first married at age 16. She fits a profile; large numbers of Western jihadists have come from socially disadvantaged homes, their lives plagued by unemployment and family turmoil.

The Tunisian man who Meryam plans to wed is in Berlin, she says, waiting for her divorce to be final. He is the first cousin of a friend of hers, and he recently entered Europe illegally, she said, after leaving Syria with a group of other Islamic State fighters of Yemeni and Chechen descent.

Meryam will be his second wife — a fact she said she fully accepts.

“I believe I have found the right man,” she said.

Together, she said, they have visited the House of Peace, where her betrothed was outraged by Sabri’s sermons against the Islamic State. She has since ceased worshiping there, and pulled out of a weekly youth group at the House of Peace. “He said . . . these people are nonbelievers.”

Like several of the most extreme youths who have gone to Syria from the West, Meryam is also a convert. She was 14 at the time. The year she converted, a close Muslim friend was killed in a neighborhood stabbing. She attended prayer vigils at his mosque, talked to some people, made the big leap. Her divorced parents were surprised but took no action to stop her.

She says she and other devout Muslims feel ostracized in German society. When she first started wearing a partial head covering, she said, she was already being turned down for jobs. When she started wearing a niqab, it became “impossible to find work.”

Meryam said her mother knows of her plan to travel to Syria but has promised to let her daughter follow her faith. Her father still does not know.

“I don’t think my father would agree,” she said. When he sees her in a Muslim veil, she said he often tells her, “ ‘If this is how you want to live, then go and live in an Islamic country.’ So that’s what I will do.”

Caught in a vice

It was two years ago that Sabri began to sense trouble among his followers at the House of Peace.

As the Islamic State was consolidating its power in Syria and Iraq, a tug-of-war for the minds of young Muslims was taking shape. He had to act.

In response, the Tunisian-born Sabri, who was imprisoned and tortured in the 1980s as a student protester before moving to Germany, called a series of youth meetings. He prominently displayed the flags of Germany and the European Union. His point: Muslims should be proud to live in a thriving Western democracy.

Sabri called the gatherings five days in a row, stringing up new flags each day. But every morning, he said, he arrived to find that some of the youths had taken down both flags before violently shredding them with pocket knives.

“They called me an unbeliever for defending democracy, which the Islamic State says is against the Koran,” he said.

To be sure, youths at the House of Peace have been seduced by radicalism in the past. Before the Islamic State, the ruthless philosophy of al-Qaeda tempted two young worshipers to try to travel to Afghanistan. But Sabri said that was nothing compared with the lure of the Islamic State now.

The House of Peace has already lost one son. Samir Malla, 27, took up arms in Syria only to be killed over the summer. Ferid Heider, who was Malla’s spiritual adviser for three years, said he could see the young man slipping away.

“He had recently divorced and began dressing in religious garb,” Heider said.

Malla, he said, also began associating with a well-known Palestinian-born radical. When Malla began handing out extremist literature inside the House of Peace one afternoon, he was finally banned from the premises.

The mosque has sought to stage interventions through relatives and friends, but, to protect its own credibility with the community, it will only go to authorities if there is a credible threat of violence. They are holding regular meetings with youths on weekends, using the time to fight fire with fire — citing passages in the Koran, for instance, to undermine the teachings of the Islamic State.

They also feel caught in a vice, between the Islamic State’s radicalism on one hand, and a sense of growing Islamaphobia within German society on the other. Right-wing protests have broken out around Germany, ostensibly against radical Islam but with overtones of a broader religious bias. A local Berlin lawmaker has already blocked the sale of a nearby city property that the House of Peace hoped to acquire for an expansion.

“It is our job to make sure our youth do not give in to discrimination and follow the wrong path,” Sabri said. “We try to reach out, we try to make them feel that this is their country, that religious tolerance is the right path. But for some of them, the message of the Islamic State has confused them.”