David Sepashvili went to Russia's mountainous Dagestan region to work in a polling station and prevent violations in Sunday's presidential election, but said a group of thugs physically stopped him from doing his job.
About 50 muscular men entered polling station 1126 in the city of Makhachkala and assaulted the independent observer stationed there before telling Sepashvili to get outside too, leaving the ballot box unobserved.
"They filled the entire station, blocked the ballot box in a line," Sepashvili, who sits on the station's election commission representing opposition candidate Grigory Yavlinsky, told AFP by phone.
The observer working at the station tried to reach the box to prevent ballot stuffing, but the men "knocked him on the ground, kicked him, and then carried him outside" before telling Sepashvili to leave the premises.
"I went to the policeman at the station, but he said he can't do anything because he doesn't have a weapon," Sepashvili said.
A video of the incident shows flowerpots in the polling station knocked over in the heat of the altercation as shouting is heard.
A man in a sweatshirt is then seen dropping ballots in the box.
The men then went to another station where a similar assault took place, Sepashvili said. "We will demand that the results at the station are annulled."
He added that regional election officials made it possible for absentee voters to cast ballots several times with multiple absentee certificates.
Dagestan, like neighbouring Chechnya, traditionally registers extremely high official turnout figures.
- 'Unprecedented' violations -
Russian opposition and independent observers have reported "unprecedented" violations in the election that is expected to give President Vladimir Putin a record fourth term.
They include alleged ballot stuffing and repeat voting, although officials dismissed most concerns by saying monitors misinterpret what they see.
Golos, the independent election monitoring association, said it registered 859 possible violations by 1200 GMT on its tracking website, along with over 2,000 calls on its hotline.
It said one observer staged an experiment with a new system that allows citizens to vote anywhere in the country by getting an absentee certificate, and successfully voted twice in Moscow at two different polling stations.
Alexei Navalny, Putin's top critic, is overseeing a campaign for a boycott and sent over 33,000 observers across the country with manual counters to see how official turnout figures differ from those of monitors.
He said at briefing in his Moscow headquarters that in some regions up to 18 percent of his observers have been removed from polling stations.
"Why? Because (the observers) are successful, and if they are not removed the authorities will not be able to show the turnout that they want."
He said there were "unprecedented violations" being reported by observers trained by his campaign, including ballot stuffing and suspicious organised voting in groups, and people being forced to vote by their employers.
Russia's Central Election Commission chief Ella Pamfilova said observers "don't interpret some situations accurately," promising to address concerns about organised voting later in the day.
Putin's election campaign spokesman Andrei Kondrashov said many reports of violations were "fake" and aimed at "discrediting the election."
Golos said ballot stuffing is "the most popular violation".
"Such cases are recorded by cameras at the stations but this doesn't stop the falsification."
A video of a polling station in the Moscow suburb of Lyubertsy showed two women methodically stuffing the ballot box with papers handed to them by one of the poll workers.
Kommersant newspaper reported that the urn in question has been sealed and the head of the polling station has been dismissed.