WARSAW, Poland — European anxiety over the presence of Muslims in traditionally Christian societies has arrived in Poland, where the capital has been blanketed in anti-Islamic posters and several hundred protesters recently showed up to denounce the construction of a mosque.

Demonstrators waved signs proclaiming “Stop Islamization,” galvanized by posters put up around Warsaw showing a woman clad in a black chador, with menacing minarets that looked like missiles peering out behind her. Counter-demonstrators, separated by a line of police, denounced them as “fascists” and “racists.”

What makes the demonstration surprising is that unlike western European countries where there are millions of Muslims, Poland, a country of 38 million, has only about 30,000 Muslims.

But at a time when Switzerland has voted to ban the construction of new mosques, when France and Belgium are considering restrictions on women covering their faces in public, and Italy’s nationalist Northern League wants to keep mosques at least a kilometer away from any churches, Islam as a political issue has arrived in Poland.

“We wanted to start a public debate,” Piotr Slusarczyk, one of the demonstrators' leaders, told the Rzeczpospolita daily. “We are warning against radical Islam in Europe.”

Samir Ismail, a Kuwaiti Palestinian doctor who has lived more than 20 years in Poland and is the leader of the newly formed Muslim League, said that for the capital's 10,000 Muslims, the mosque would simply be a place to pray. He pointed out that the community has been careful not to offend, opting for a 16-yard high minaret instead of the 25-yard one approved by the building permit.

“We don’t want to create misunderstandings,” he told the Gazeta Wyborcza newspaper. “We are aware that we have a problem with being accepted.”

The friction around Poland’s still tiny Muslim minority is a sign of the country’s growing normalization and integration into the European Union. Immigrants were almost unknown in communist times, but as Poland becomes wealthier, it is starting to attract outsiders, from Ukrainians working on construction or as domestic help, to Muslim Chechens escaping Russian repression in their homeland.

In one sense, Poland’s growing diversity is a return to the past. Before World War II, Poland was a multinational stew, with ethnic Poles making up only about two-thirds of the population. The country had large numbers of Ukrainians, Jews and Germans, as well as a small Muslim minority — Tatars descended from the hordes of Genghis Khan who had terrorized Europe in the Middle Ages.

Several thousand Tatars had settled in Poland and Lithuania in the 14th century, and, despite losing their language, never lost their religion.

World War II left Poland a very different country. The Jews had been mostly murdered by the Germans, and most of the survivors left after the war. Germans were expelled, and by shifting Poland’s borders hundreds of miles to the west, there were no large Ukrainian and Belarusian minorities. After 1945, Poland was almost completely monoethnic — one of the only minorities left were the Tatars, who have two villages in northeastern Poland, each with a small mosque.

New Muslim migrants, like Samir Ismail, have very little in common with the Tatars, who have been well integrated into Polish life for centuries — they even had their own cavalry unit before the war. Ismail and other Muslims formed their own organization in 2003, designed to advocate for the interests of new immigrants, including the need to build themselves a place to worship.

From that time they have been trying to build a mosque in Warsaw with the help of Saudi sponsors. As the project has neared completion, it has begun to arouse the ire of some Polish nationalists, who fear that their country could soon have the same issues with Muslim minorities as countries in western Europe.

“We have the example of other countries where the idea of freedom of religion is abused,” said Slusarczyk.

But Poland’s laws do not allow for any religious discrimination.

“The decision permitting this investment has been taken long ago,” said Tomasz Andryszczyk, a spokesman for the Warsaw city government. “What are we supposed to do? It would be bad if this project ran into any troubles.”