"Belarusian law enforcement officers detained 32 militants of the Wagner foreign private military company near Minsk," BelTA wrote, citing sources in law enforcement. Another Russian citizen reportedly linked to the company was detained in the south of the country.
"More than 200 militants were reported to have arrived in our territory to destabilize the election campaign," the agency said.
The men's behavior was "uncharacteristic for Russian tourists" while their "uniform military-style clothing" drew attention, according to BelTA.
Belarusian authorities have not yet informed the Russian Embassy in Minsk of the detentions, ambassador Dmitry Mezentsev said on Wednesday.
Russian author Zakhar Prilepin confirmed that "two or three" of the arrested Russians had served in his former unit during the war in eastern Ukraine.
The Wagner private military company has been reported as linked to Russian businessman Yegeny Prigozhin, also known as “Putin’s chef” for his Kremlin catering contracts. Wagner mercenaries have taken part in multiple armed conflicts, such as the war in eastern Ukraine and the Syrian civil war.
Belarus has seen multiple mass protests in the run-up to its August 9 presidential election, in which incumbent leader Alexander Lukashenko is seeking to secure his sixth consecutive term.
Lukashenko's main rivals Sergey Tikhanovsky and Viktor Babaryko have been detained and charged with crimes that could see them jailed from three to twenty years. A third opposition candidate, Valery Tsepkalo, was barred from taking part in the election and fled the country last week fearing to avoid persecution.
Hundreds took to the streets in the support of the candidates following their arrest. Belarusian authorities have detained more than 250 people at protests this month.
Tikhanovsky's wife Svetlana has taken his place as a stand-in candidate in the vote, and has received the backing of both Tsepkalo and Babaryko after being admitted to the election ballot on June 14.
Svetlana Tikhanovskaya's campaign now presents a united opposition front to Alexander Lukashenko's candidacy in what analysts call the toughest re-election campaign in his 26 years in power.
Lukashenko, who has been in power since 1994, previously accused foreign powers "both the West and from the East" of attempting to destabilize the situation in Belarus.