Russia's Federal Protective Service has announced that Red Square in Moscow is being closed off for the next five days.
The closure, which extends to the Lenin Mausoleum and most Kremlin attractions, will last until June 12, when the country marks Russia Day, a national holiday celebrating Russia's declaration of state sovereignty in 1990.
Large opposition rallies are planned across Russia to coincide with the commemorations.
The Russian parliament this week approved a bill that would impose fines of up to $9,000 on people participating in unsanctioned rallies.
Vladimir Putin, whose return to the Russian presidency has sparked a season of massive protests rallies, has yet to sign the bill into law.
The Kremlin's Human Rights Council says the legislation is unconstitutional.
Based on reporting by Interfax and RIA Novosti