A Moscow court on Friday placed opposition leader Alexei Navalny under house arrest for two months.
On Wednesday, the Investigative Committee accused Navalny of repeatedly breaching the travel restrictions that were placed on him as part of a fraud inquiry and asked for the constraints to be tightened.
The Basmanny District Court granted the request, which bars Navalny from using telephones, sending and receiving mail, and using the Internet without permission investigators, Lenta.ru reported.
He is also prohibited from commenting on the criminal case brought against him and will be allowed contact only with his family during the two months.
Navalny and his brother Oleg are being investigated on suspicion of defrauding the Russian branch of French cosmetics company Yves Rocher out of 26 million rubles ($720,000).
A reporter from Slon.ru cited Navalny as saying on Friday that the investigators' demands were aimed at clamping down on his political and social media activities.
He is currently serving out a seven-day jail sentence for disobeying police orders at an unauthorized rally in Moscow in support of the defendants in the so-called Bolotnaya case on Monday.
Investigators said in January that Navalny had violated his bail terms by traveling out of Moscow's city limits and into the surrounding Moscow region.
However, Navalny insisted that the authorities had amended the restrictions to let him go to the Moscow region.