“There is a huge group of Muslims that are not Tatars,” said Dzemil Gembicki, caretaker of the mosque in Kruszyniany. “We want to stick with our own traditions. We are afraid that the huge group of Muslims from other places may cause us to lose the traditions of Polish Tatars.”

Tomasz Miskiewicz, the mufti of Poland and a Lipka Tatar, said that “the situation of Tatar society here in Poland is on the edge.”

“A lot has changed,” he said in an interview in the eastern city of Bialystok.

Lipka Tatars are descended from Turkic people from Central Asia who migrated to the Baltic region in the 14th century. Those who live in what is now Poland have historically been centered in the Podlaskie region, a heavily forested area in the northeast where bison and wolves still roam and where the countryside is peppered with Orthodox and Catholic churches, synagogues and mosques. The religious diversity is striking for a country that is otherwise 94 percent Roman Catholic.

“I am Muslim, I am Tatar, I am Polish,” said Ms. Bogdanowicz, who runs a Tatar restaurant in Kruszyniany. “It cannot be divided.”