Three prominent opponents of Russian President Vladimir Putin have reportedly been detained for disturbing the peace.
Alexey Navalny, Sergei Udaltsov and Ilya Yashin were detained while protesting against the torture of prisoners along with dozens of others in front of the country's secret police headquarters on Saturday.
The unauthorised protest was spurred by the abduction a week ago Friday of Kremlin-opponent Leonid Razvozzhayev in the Ukraine.
Razvozzhayev has accused the secret police of kidnapping and torturing him.
He and Udaltsov have been charged by the government with a conspiracy to organise violent protests.
Human rights groups have criticised the latest arrests as a part of the repressive actions of the Kremlin against opponents.
Navalny is a lawyer and a vocal critic of corruption; Udaltsov leads the opposition Left Front movement; while Yashin has organised anti-Putin protests in the past.