Police detained dozens of anti-Kremlin activists in Russia's second city on Wednesday after 300 gathered to protest restrictions on the constitutional right to free assembly.
"Russia will be free," shouted activist Andrei Dmitriyev before police dragged him to a waiting bus in the centre of Saint Petersburg.
Around 30 activists were taken to a local police station.
Russian opposition groups last year began to hold rallies on the last day of each month to defend article 31 of the constitution, which guarantees the right to free assembly.
Activists say this gives them the right to hold protests without prior permission, which is regularly denied to opposition groups. Police routinely break up rallies not rubber-stamped by the authorities.
Street protests are one of the few outlets available to anti-Kremlin activists, who are blocked from state media and often denied registration to stand in elections.
At least a dozen people were arrested on Wednesday at a similar rally in Moscow attended by around 50 people.
ReutersGüncelleme Tarihi: 01 Nisan 2010, 10:50