MOSCOW, Nov 4 (AFP) - Russia on Wednesday marked its new annual day of national unity, established under strongman leader Vladimir Putin, with a string of mass rallies including pro-Kremlin youth and far-right extremists.

The November 4 Day of National Unity has been celebrated since 2005 when Russia's then president Putin created the holiday to replace the November 7 commemoration of the 1917 October Revolution.

Putin's successor President Dmitry Medvedev said the national day "gives us reason to believe that we are indeed a united people, a people capable of overcoming the biggest problems which have been our fate more than once."

Russians were "a people that has defeated the enemy many times. A people that endured deprivation but stayed strong and courageous," he said in a speech in the town of Suzdal east of Moscow carried on state television.

This year, the day was to be marked by nationalist-tinged rallies, with the biggest expected to be by the pro-Kremlin youth group Nashi which has vowed to bring 20,000 of its supporters out by the river in central Moscow.

"November 4 is the day when Russia remembers its great history. All those with a Russian passport, who know Russian, who study the laws of our country... are invited irrespective of ethnicity," Nashi said in a statement.

But permission has also been granted to the far-right Movement Against Ilegal Immigration (DPNI) for a so-called "Russian March" expected to be attended by 2,000 people in southeast Moscow.

"Be polite and respectful... Remember all Russians are brothers... Do not use gestures that could be used by the media to discredit the Russian March," the DNPI told its supporters in a statement.

By contrast to the permission given to the right-wing group, Moscow police last Saturday arrested 50 opposition protesters in the centre of the Russian capital for staging an unsanctioned demonstration.

The November 4 holiday marks the day in 1612 when Prince Dmitry Pozharsky forced an invading Polish-Lithuanian force to leave its positions inside the Kremlin.

This brought to an end a chaotic period in Russian history known as the Time of Troubles and opened the way for the establishment of the Romanov Dynasty that ruled Russia until the Revolution.

However most Russians remain unaware what the holiday is for, according to a poll published by the Russian Public Opinion Research Centre (VTsIOM).

Only 16 percent could name the holiday as the Day of National Unity while a mere two percent could make any links to the events of the 17th century with the holiday, the centre said in a poll of 1,600 people across Russia.