Amnesty International said yesterday Russian authorities were arresting and harrassing critics such as opposition leader Garry Kasparov to silence them in the run-up to the December 2 parliamentary elections.
The rights group called for the immediate release of Mr Kasparov, a former international chess champion who is serving a five-day sentence at a Moscow detention centre for leading a protest on Saturday against President Vladimir Putin. He is due to be released today.
"Amnesty International considers him to be a prisoner of conscience and calls for his immediate release," the rights group said in a statement titled "Russian Federation: systematic repression on eve of elections".
"Several witnesses told Amnesty International that they had overheard conversations among the police indicating that it had been planned in advance of the march to detain Garry Kasparov."