Tens of thousands of Communists on Saturday turned out in Russia to mark the anniversary of the 1917 October Revolution, shrugging off the Kremlin's cancellation of the day as a national holiday.
Waving red hammer-and-sickle flags, thousands marched marched down Tversyaka Street in central Moscow to hold a meeting by the statue of Karl Marx close to the Bolshoi Theatre.
Some 154,000 people were expected to turn out across Russia for demonstrations marking the revolution while 10,800 members of the security forces were to be on hand to keep order, the Interfax news agency said.
Interfax said the leader of the far-left party Left Front Sergei Udaltsov and up to 20 of his activists were detained after the meeting but otherwise the rally appeared to pass peacefully amid a heavy police presence.
The October Revolution of October 25, 1917 (November 7, 1917 according to the new calendar) ousted the post-imperial provisional government and installed the Soviets led by Vladimir Ilyich Lenin in power.
In 2005, then president Vladimir Putin to the dismay of die-hard Communists installed November 4 as a new day of Russian National Unity to replace the November 7 holiday.
In its place, the Moscow authorities now on November 7 re-enact the Red Square parade that took place on November 7, 1941 when the Soviet Union was reeling in the war with Nazi Germany.
This year for the first time, T-34 tanks which were the mainstay of the Soviet army in World War II again rolled along the Red Square cobbles as part of the re-enactment.