MOSCOW       -  More than 600 people have been detained over an unauthorised protest in Moscow, amid reports of police violence.

Protesters had gathered in the Russian capital after authorities disqualified a number of opposition candidates from standing in local elections.

Video from the rally shows officers using their batons against demonstrators while making arrests. Russian officials initially said there had been just 30 arrests and 350 attendees. Monitoring group OVD-Info, which runs a hotline for reporting detentions, had been keeping a running toll, which rapidly jumped from a few dozen arrests to several hundred.

Officers in riot gear had earlier moved into the capital and warned people not to protest. A Russian news agency reported that one police officer had been injured while making an arrest.

But protesters also reported mistreatment at the hands of police.

Footage broadcast on Russian television and shared on social media showed police pin people to the ground, kicking or using batons on them. One man told Dozhd TV channel that one such person had been removed from the police van for a beating after asking officers to identify themselves.

Alexander Svidersky, a member of a district electoral commission, said he was arrested while out with his dog, which he managed to pass off to an acquaintance before being bundled into a police van. OVD-Info reported he said he was later was taken out and hit around the kidneys before being dragged to another van.

Detainees at one police station also told OVD-Info they were threatened with having their fingers “cut off” if they did not allow their fingerprints to be taken.