By Darya Korsunskaya
MOSCOW (Reuters) - President Vladimir Putin said on Thursday Moscow must prevent a "color revolution" in Russia and stop extremism, warning of the threat posed by illegal immigration and "radical" Internet sites that recruit youths.
Putin's comments at a meeting of his advisory Security Council on combating extremism, underlined his wariness about Russia being hit by a popular uprising like those in other former Soviet republics known as the color revolutions.
"In the modern world extremism is being used as a geopolitical instrument and for remaking spheres of influence. We see what tragic consequences the wave of so-called color revolutions led to," he said.
"For us this is a lesson and a warning. We should do everything necessary so that nothing similar ever happens in Russia."
Putin's comments also point to concern about outside interference. He said on Tuesday the United States is trying to subjugate Russia, blames the West for the overthrow of a Moscow-backed president in Ukraine in February and accused Washington of stoking protests against him in the winter of 2011-12.
The annexation of Crimea in March and a surge of patriotism, in Russia over the crisis in Ukraine, fed by pliant media, has boosted Putin's popularity at home and neutered the opposition.
But he has been wary of political and social upheaval since the protests against him swept big cities such as Moscow and critics say he has stifled dissent and persecuted potential rivals to tighten his grip on power ever since.
At the time of the protests, Moscow also signaled its concern about the possible spread of unrest from the so-called Arab Spring uprisings in the Middle East.
Putin fears the unrest in Ukraine could encourage protests in Russia itself, especially as Western sanctions bite and an economic slowdown starts to hurt. Russia already faces a persistent Islamist insurgency in the North Caucasus.
"Extremist ideology is gaining momentum in the virtual sphere," Putin said, criticizing websites "through which extremist organizations are trying to recruit followers" and saying this should be prevented - without saying how.
He said many problems were tied to illegal migration and added: "It is necessary to strengthen control over (that)."
Critics say Putin is tightening restrictions on opponents dissent while the world's eyes are turned to Ukraine but he said combating extremism had "nothing to do" with cracking down on dissent.
(Writing by Gabriela Baczynska, Editing by Timothy Heritage)