Travel ban for Russian anti-Putin activist Udaltsov
One of the best-known figures in the anti-Putin protest movement, Sergei Udaltsov, has been placed under a travel ban by investigators in Moscow.
Russia's FBI-style Investigative Committee (SK) confined him to Moscow after questioning him about an alleged plot to seize power in Russia.
Mr Udaltsov denied the allegations and said a "new repression" was under way.
Elsewhere, President Vladimir Putin sacked one of his ministers after publicly criticising him last month.
No reason was given for dismissing Regional Development Minister Oleg Govorun and replacing him with Igor Slyunyayev.
However, last month, in a dressing-down broadcast on TV, the Russian leader rebuked Mr Govorun for failing to deliver on his election promises to help people living in sub-standard housing in the regions.
An unnamed Kremlin source quoted by Russian business newspaper Vedomosti said the main reason for Mr Putin's dissatisfaction was Mr Govorun's poor handling of the Krymsk flood disaster clean-up.
Along with Mr Udaltsov, at least two other people were also placed under investigation by the SK.
In Twitter messages, Mr Udaltsov, a radical leftist, said his apartment had been searched and he had been taken to SK headquarters for interrogation.
"This is lawlessness and provocation and I hope that society will not be silent," he was quoted as saying by Russia's Interfax news agency.
A documentary last week on Russia's NTV channel, which is seen as close to the Kremlin, showed what it said was footage of the activist meeting officials from Georgia to discuss mounting a coup in Russia.
In a statement released on Wednesday, the SK said it had begun an investigation into Mr Udaltsov, Leonid Razvozzhayev, Konstantin Lebedev and others on the basis of the allegations made in the documentary, Anatomy Of A Protest II.
If convicted, Mr Udaltsov and the others face prison sentences of between four and 10 years.
Correction, 19 October 2012:This story originally said that Mr Udaltsov had been placed under house arrest but it has now been clarified that he has been barred from leaving Moscow.