Russia said on Thursday two U.S. citizens had been deported for violations of immigration laws, following local media reports that identified them as members of the Mormon church, and that two other Americans were in custody.
Russian media named the two as Kole Brodowski and David Udo Hague and said they had been ordered to leave Russia by a court in the southern port of Novorossiysk on Thursday, Reuters said.
It described them as volunteers with the Church of Jesus Christ of Latter-day Saints, or Mormons.
"I can confirm reports of the detention of U.S. citizens for breach of migration laws," foreign ministry spokeswoman Maria Zakharova said. "Four were detained, two were deported by the decision of the court."
The Mormon church was not immediately available for comment, Reuters said.
There have been several high profile arrests of U.S. citizens in Russia in recent months.
Paul Whelan, a former U.S. marine accused of spying, saw his detention extended last month for a further three months as authorities continue to investigate the case.
A prominent U.S. investor, Michael Calvey, was detained last month on allegations of stealing 2.5 billion roubles ($37.79 million). He denies the allegation.
More than 100 criminal cases have also been opened in Russia against Jehovah's Witnesses, another Christian denomination, with a Danish adherent of the faith recently jailed for six years.
KSL TV in the American state of Utah, where the Mormon church is based, quoted the father of one of the two detained men as saying they had been held on Friday on suspicion of teaching without a license.