Two members of the protest group Pussy Riot, Maria Alyokhina and Nadezhda Tolokonnikova, say they were detained by police while they were walking around Sochi, where Russia is staging the Winter Olympics.
The police were not immediately available for comment.
Russian president Vladimir Putin has staked his reputation on the Winter Games, hoping they would show the world Russia's modern face more than two decades since the fall of the Soviet Union.
Both women said on Twitter that police used force and threw them in a police van. Alyokhina said they had been detained on suspicion of committing a crime, but did not give details.
Tolokonnikova (24) and Alyokhina (25) had recently returned to Russia after a tour through Europe and the United States following their release from prison in December under an amnesty that Tolokonnikova said was a stunt by Mr Putin to improve Russia's image before the Olympics.
They had been serving two-year jail terms for hooliganism motivated by religious hatred after performing a profanity-laced protest song against Mr Putin in Moscow’s main cathedral in February 2012.
“At the time of our detention, we weren’t engaged in any protests, we were walking around Sochi. We were walking,” Tolokonnikova said on Twitter.
The two women were in Sochi with other members of Pussy Riot to record a musical film called “Putin will teach you to love the motherland”, Tolokonnikova’s husband said on Twitter.
Reuters