A Moscow court has ordered Russian protest leader Alexei Navalny to be placed under house arrest after a request from investigators probing an alleged embezzlement case.
Navalny, who last year was given a suspended five-year sentence in a separate timber embezzlement case, faces charges in this case along with his brother Oleg of stealing and laundering a total of 51 million rubles ($A1.57 million) from cosmetics company Yves Rocher and a Russian firm.
Investigators had already made Navalny sign a pledge not to leave Moscow but asked for his restrictions to be stepped up to house arrest, arguing he had repeatedly violated the restrictions imposed on him.
As well as being unable to leave his home in the Moscow region, the tough new restrictions imposed by a district court mean that Navalny will only be able to talk to relatives, investigators and his defence.
Crucially for a figure who has emerged as one of the main challengers to President Vladimir Putin through a widely-followed blog, he will not be able to use the internet.
Navalny will also not be able to send or receive letters or talk to the press. The term of the house arrest is until April 28 but it can then be extended.
"He will only be allowed to leave his home with the permission of investigators," his spokeswoman Anna Veduta wrote on Twitter.
Navalny and his supporters argue that like his previous conviction the current case is another ruse from the Kremlin aimed at eliminating one of Putin's most dangerous opponents from politics.
The protest leader is serving a brief week-long administrative detention sentence handed out this week for disobeying police orders at a demonstration over the jailing of a group of activists opposed to Putin.
He is due to walk free from that term on March 3 but under the court ruling he will then immediately have to begin the period of house arrest.
