This medieval city of timber-framed buildings and cobblestone streets is on the front lines of the escalating culture war over Islam in the West.

Donald Trump may be calling for a ban on Muslims visiting the United States. But on this side of the Atlantic, Islam is also under fire, with political opposition to the faith growing as an anti-Muslim message emerges as the rallying cry of Europe’s far right.

In few places is the shift more startling than here in Germany, where Islamist terrorism in neighboring nations and a record wave of Middle Eastern migrants are testing the national will to protect minority rights adopted after World War II.

Once a libertarian force opposed to the euro and Greek bailouts, the fast-growing Alternative for Germany Party (AfD) has now squarely joined the anti-Islam ranks. In recent weeks, the AfD unveiled a scathing denunciation of the faith, warning against “the expansion and presence of a growing number of Muslims” on German soil. Adding further fuel to the party’s crusade, German authorities on Thursday arrested three Syrian men who had posed as migrants for allegedly plotting an attack on the historic center of Düsseldorf in the name of the Islamic State.

To protect women’s rights, national security and German culture, the party – supported by almost 1 in 6 voters – is calling for a ban on headscarves at schools and universities and is preparing to release an anti-Islam “manifesto” based on “scientific research.” Here in the former communist east, the party has gone further – startling local Muslims by launching a campaign to stop the construction of what would be Erfurt’s first-ever mosque.

According to city records, 75 percent of Erfurt’s 200,000 residents say they have “no religion.” But AfD officials are outraged by the thought of minarets rising only a few tram stops away from the steeples of Erfurt’s ancient Christian churches.

“This issue is too important to remain silent about,” said local AfD politician Stefan Möller. “We owe it to our country to speak out. We are patriots.”

Muslim leaders and progressive politicians, meanwhile, are sounding the alarm, while calling the AfD’s move against Islam a sign of the times. This year at least two German universities have closed Muslim prayer rooms, arguing that places of higher education should be secular and that Islam should not receive “special treatment.” They are encouraging Muslims who want to pray to use generic “rooms of silence” designed for all students.

In Germany, as in other parts of Europe, there has also been a recent spat of attacks on mosques, including attempted arsons and vandalism.

Some here – and not only Muslims – are deeply worried by the trend.

“The crematoriums for the concentration camps [of World War II] were built in Erfurt,” said Bodo Ramelow, the left-wing governor of the state where Erfurt is located. “Buchenwald and Dora concentrations camps were here. The first big wave of racism was directed against our fellow Jewish citizens . . .We must never again allow a majority vote to prevent a minority from thriving.”

Muslim leaders see rising opposition in Germany as part of the same phenomenon that has turned Islam into a campaign issue in the United States, but also in France, Austria, Holland, Poland and other nations in Europe.

“For the first time [since World War II] there is a party again attempting to existentially constrain an entire religious community and to threaten it,” Aiman Mazyek, chairman of the Central Council of Muslims in Germany, said about the anti-Islam stance of the AfD. “This reminds us of the times of Hitler.”

Political opposition in Europe to more conservative forms of Islam has been growing for years. In 2009, Switzerland effectively banned a new mosque and a year later, France passed a law banning headscarves in public. But Muslim leaders fear a resurgence of anti-Islam sentimentsthroughout the West.

In the United States, Trump is targeting Muslims, while in Austria last month, a “Muslim invasion” of migrants fleeing war became the dominant theme of a presidential race narrowly lost by the far right. In Britain, London’s first ever-Muslim mayor faced a campaign in which even Prime Minister David Cameron sought to link him to extremists.

In France, acts of violence against Muslims surged more than threefold in 2015, jumping from 133 incidents to 429, according to the country’s Interior Ministry. In May, Polish police entered university dorms in Krakow to question a number of foreign students about connections to terrorism, prompting allegations of racial profiling and Muslim-bashing.

In January, the Danish city of Randers passed a resolution requiring public institutions to serve pork. Supporters rallied in favor of the bill by saying that Danish food culture should trump the religious requirements of Muslim immigrants.

In April, the Italian province of Veneto adopted a change in a law that critics say makes it harder to build mosques.

“I’m absolutely against the construction of new mosques,” Luca Zaia, Veneto’s governor from the right-wing Northern League, told the Nuova di Venezia newspaper. “I’ve already met some of these preachers, and I told them clearly that sermons need be pronounced in Italian, for reasons of transparency.”

Germany has long been a bastion of tolerance in Europe, with many pointing to World War II history as an example of the danger when religious and ethnic minorities are targeted.

Some AfD supporters point to the growing influence of radical Islam in Germany as evidence of what happens when the faith is left unchecked. In 2014, for instance, a group of ultra-conservative Islamists staged a publicity stunt in the German city of Wuppertal, dressing up as “Sharia Police” – a reference to Islamic religious law – while allegedly telling bystanders not to drink alcohol or visit nightclubs.

Islam’s critics, although insisting they have nothing against progressive Muslims, are increasingly taking aim at the faith more broadly. They point to a lack of respect for gays and lesbians, as well as women, allegedly shown by some Muslims – including suspects in a series of sexual assaults on New Year’s Eve in the German city of Cologne.

But opponents of the right wing argue that its own stances against gay rights and in defense of “traditional” roles for women suggest that anti-Islam positions are merely being used a political ploy to win votes.

The AfD “basically represents the same authoritarian, homophobic and sexist – in short: inhumane – position as ultraconservative Islamic associations,” Mina Ahadi, an Iranian dissident and critic of fundamental Islam, wrote in an open letter to the group.

An attempted meeting between the AfD leadership senior Muslim officials in Germany broke down last month, with both sides blaming one another. To produce materials arguing that Islam is incompatible with German democracy, the AfD is relying on authorities such as Tilman Nagel, a former professor of Islamic Studies at Göttingen University who, in a telephone interview, lashed out at “political correctness.”

“The fundamental principles of Islam can’t be reconciled with our free constitution,” he said.

In Erfurt, the AfD’s opposition to a new mosque has stunned the small local community of 70 Muslims who are seeking permission to build it, the city’s first, on a grassy patch of land in an industrial quarter on the outskirts of town. In fact, the AfD only found out about their plan when a local Muslim leader informed them of it during a meeting last month.

“I could see the hate in their eyes when I told them,” said Suleman Malik, a 33-year old refugee councilor and immigrant from Pakistan who is leading the effort .

“They want to violate our freedom of religion, but I don’t think they will succeed,” he said. “This is a national issue now, and I don’t think Germany wants to see this happen.”

(c) 2016, The Washington Post · Anthony Faiola