Budapest: A friend writes on Facebook that her underage son has been arrested as he tried to take part in an anti-corruption protest in Moscow.

The comments are a mixture of pride and concern for young Sasha. Police grabbed him at the metro exit before he even reached the demonstration. He was held for several hours at the police station and came home bruised.

A young protester shouts slogans at Dvortsovaya (Palace) Square in St Petersburg on Sunday. Credit:AP

It's a sign the Russian presidential election season has started with cries of frustration from the younger generation and the prospect of a harsh crackdown by the Kremlin.

Sasha, 17, was one of hundreds of peaceful citizens detained in cities across Russia on Sunday after they defied the authorities and came out in support of opposition figure and blogger Alexei Navalny who dares to challenge Vladimir Putin for the presidency next year.