Russia’s security services, however, were not about to let that happen.

An aggressive crackdown that began before last year’s Winter Olympics in Sochi never ended, leading to widespread arrests not just in the predominantly Muslim Caucasus but throughout European Russia and as far north as Novy Urengoi, just below the Arctic Circle, where the authorities this year demolished a building that had housed a mosque and an Islamic preschool.

The pressure by the security services, in the name of combating extremism, has set off a wave of refugees seeking safety and religious freedom, especially in Turkey and the United Arab Emirates.

Muslim leaders and human rights advocates say that Russia’s often brutal approach has also added to the appeal of the Islamic State, with the Russian authorities saying recently that hundreds of Russian Muslims have gone to Syria.

For moderate converts who have fled Russia, one obstacle to obtaining political asylum, or even more basic social service help, has been a lack of awareness among some officials that Slavic Muslims even exist.

“Lawyers who were to speak about our problem with the authorities, they said that the first thing to do was to explain to the Turkish government that there is a group of ethnic Russian Muslims, because no one has the slightest idea of this,” said Dmitri I. Chernomorchenko, who was born to Christian parents in Cherkessk in the North Caucasus, but took the name Khamza when he converted and now lives in Istanbul.

“We know Tatars, Chechens; we know that Dagestanis of various ethnicities are killed, but that there are suppressed Russians and that you actually have a large ethnic group, we don’t know about this,” Mr. Chernomorchenko said, explaining the reaction he faced when he moved to Turkey.

The aggressive scrutiny by the Russian security services on converts to Islam is based partly on a belief, shared by some experts on religious fundamentalism, that they are more likely to embrace extremism and carry out terrorist attacks.