Moscow (CNN) More than 300 people were arrested Saturday during protests in Moscow calling for fair and free upcoming local elections, according to an independent monitoring group.

During the unauthorized demonstration , 311 people were arrested, said OVD-info. However Russia's Ministry of Interior put the number of detainees much lower, at 30, and said that only 350 people had taken part in the protests.

Among those arrested was prominent activist Lyubov Sobol, an ally of high-profile opposition leader Alexei Navalny . She was shown being removed from a taxi and bundled into a van by police moments before the demonstration started, in Reuters footage.

Protesters take to the streets in central Moscow Saturday.

It is the latest in weeks of protests against independent and opposition candidates being barred from the ballot in municipal elections scheduled for September.

Authorities said candidates were barred from running because they had failed to obtain a sufficient number of signatures to be put on the ballot paper. Opposition politicians have rejected this allegation.

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