Police in St. Petersburg have been filmed dragging a local election monitor out of a building as observers accuse officials in Russia’s second-largest city of staging the “dirtiest” campaign in the country.

No official results have been declared in the five days since St. Petersburg held the municipal vote, leading some election commission members to claim that officials there are preparing falsifications. Election-day footage showed one observer being punched after flagging potential violations and reports said at least two commission members had been attacked Sunday.