Yelena Vasilyeva, the head of the Murmansk branch of the opposition United Civic Front, says journalist Larisa Arap was detained on July 6 and is being held at a closed psychiatric hospital in a remote part of the Murmansk region.
Arap recently published articles alleging child abuse at psychiatric institutions.
She also spoke at a June 12 demonstration organized by the United Civic Front.
A spokesman for the regional governor's office, Nikolai Sigin, said he was unfamiliar with Arap's case but that it was "impossible" anyone could be hospitalized for their political convictions.
(AFP, Ekho Moskvy)