Russian law enforcement officials have detained two members of the Mormon church in the Black Sea port of Novorossiisk on unspecified charges.
The state-run news agency TASS reported on March 6 that a district court in the city had found two unnamed Americans guilty of violating Russian immigration laws.
In a statement e-mailed to RFE/RL, Eric Hawkins, a spokesman for the U.S.-based church, said the two unnamed individuals were taken into custody on March 1 during a local church meeting, but gave few other details.
"Two of our volunteers serving in Novorossiisk, Russia, were detained by authorities Friday evening while engaged in a meeting at a local meetinghouse. While we are grateful these young men are reportedly in good condition and are being treated well, we are troubled by the circumstances surrounding their detention," Hawkins wrote.
"They have both spoken to their parents," the spokesman also said. "We will continue to work with local authorities and encourage the swift release of these volunteers."
A U.S. State Department spokesman confirmed the detentions, but gave no further information.
The U.S. Embassy in Moscow "will be following this case closely and will provide all appropriate consular assistance," the spokesman told RFE/RL, speaking on condition of anonymity. “Due to privacy considerations, we do not have any additional information at this time.”
In Moscow, Foreign Ministry spokeswoman Maria Zakharova said "several U.S. citizens" had been detained in Novorossiisk, but directed further questions to law enforcement agencies.
A television station in Utah, where the Mormon church is headquartered, said the father of one of those detained had posted a message to Facebook saying his son was detained while teaching an English class.
The Facebook post could not be immediately verified and the father, identified by the station as Kyle Brodowski, did not respond to messages seeking comment.
Novorossiisk is Russia's largest port on the Black Sea and a major export hub for commodities like oil and grain. It's also home to an important terminal for the Black Sea naval fleet.
Formally known as the Church of Jesus Christ of Latter-day Saints, the Mormons have long been a presence in Russia, teaching English classes and proselytizing.
According to church figures, registered Mormons grew from 300 in 1991 to more than 14,000 a decade later. Today, the church claims 23,000 adherents in Russia.
The detentions come with growing scrutiny within Russia on religious groups that don't qualify as one of the four religions formally recognized.
Freedom of religion is formally guaranteed in Russia but legislation sets out Orthodox Christianity, Islam, Judaism, and Buddhism as the country's four traditional religions.
Other major Christian denominations like the Roman Catholic Church have also been allowed to operate openly and largely without restrictions, though the Vatican and Russian Orthodox leaders have clashed in the past over ownership of church property dating back to the Bolshevik Revolution.
But denominations with a smaller presence in Russia -- Baptists, Pentecostalists, Mormons, and others -- have long been viewed with hostility from state officials and religious authorities. Many have long complained that the 1997 law setting up registration and administrative procedures were onerous and expensive to comply with.
A measure signed into law by President Vladimir Putin in 2016 put further restrictions on smaller religious groups.
In 2017, Russia’s Supreme Court ruled that the Jehovah’s Witnesses -- a U.S.-based denomination that has long been viewed with suspicion by some governments for its members' positions on military service, voting, and government authority in general -- should be classified as an extremist group, and ordered it banned.
In recent months, Russian law enforcement has stepped up raids against Jehovah's Witnesses throughout the country.
Last month, a Danish member of the denomination was found guilty of extremism and given a six-year prison sentence.
And several Jehovah's Witnesses in the Russian city of Surgut said they had been recently beaten, suffocated, or shocked during interrogations by police about their group's activities.