MOSCOW - The websites of Russia's main independent news sources became inaccessible on Tuesday as protesters gathered in Moscow for a march against President Vladimir Putin's third Kremlin term.
The site of the Moscow Echo radio station went down about a half hour before protesters started to gather on central Pushkin Square for a walk to the site of a rally organisers hope will draw 50,000 people.
The Dozhd (Rain) TV website and that of the prominent opposition Novaya Gazeta twice-weekly newspaper also could not be accessed as the event officially got under way at 0800 GMT.
The websites of Russia's main media sources -- including Kremlin-allied papers and state-controlled television stations -- were all accessible and operating without delay.
A Dozhd newscaster said their station's website was the victim of a distributed denial-of-service (DDoS) attack of unknown origin.
Opposition leaders accuse pro-Putin youth groups of staging such attacks with the Kremlin's tacit approval at sensitive political times.
The same websites became inaccessible during disputed December parliamentary elections that sparked the biggest wave of protests against Putin's dominant 12-year rule.
No one claimed responsibility for that attack.
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