At least 17 protesters rallying against the results of a local election in Far East Russia have been detained Tuesday night after security officials threw a smoke grenade into the bus they were in.

Hundreds of protesters have demanded a re-do of Sunday’s vote in the republic of Buryatia’s administrative center of Ulan-Ude, where a pro-Kremlin candidate was elected mayor. Intermittent clashes broke out and several protesters have been detained since the spontaneous demonstrations began in Ulan-Ude on Monday.

“People were sitting in a bus when a smoke grenade flew in. They smoked us out of the bus and put us on our knees,” Interfax cited one of the participants as saying.

The regional Interior Ministry said in a statement that 17 people were detained. One of the activists told the U.S.-funded Radio Free Europe/Radio Liberty news outlet’s regional affiliate that all but one of the detained protesters have since been released.

Both the police and the region’s human rights commissioner have claimed that protesters used tear gas against police, resulting in one of the officers receiving an eye injury.

Two people who were on the bus told the independent Novaya Gazeta newspaper that the police had thrown tear gas, not a smoke bomb.

Bair Tsyrenov, a communist member of the local legislative assembly, has called on supporters to attend new rallies that he said he plans to get approved by the authorities. The newly elected mayor, Igor Shutenkov, ordered to seal off the square outside the regional administrative building where the protesters had gathered.

The head of Buryatia on Tuesday appealed to protesters in a video address to accept the outcome of the vote, calling the police response “restrained and professional.”

Monday’s protest initially broke out in support of detained followers of Alexander Gabyshev, a shaman who has been walking on foot to Moscow to “expel” President Vladimir Putin.