"The embassy has not received an official notification of the detention of Russian citizens on the territory of the Republic of Belarus. [We] have requested official information from the competent authorities of Belarus", the embassy said on Twitter.
Earlier in the day, Belarusian state-run news agency Belta reported, citing an unnamed law enforcement official, that the 33 persons detained for planning to destabilise the situation in the country ahead of the presidential vote were Russians.
The detention took place on the night into Wednesday. Thirty-two "militants from the Wagner Group paramilitary organisation" were detained not far from the Belarusian capital of Minsk, and one more person was detained in the south of the country, Belta reported.
The news agency added that it had been revealed previously that over 200 militants arrived in Belarus to destabilise the situation there.
Belta claimed that the arrested individuals had arrived in Belarus late on 24 July, checked in at a hotel in Minsk and were supposed to check out on 25 July, but instead stayed until 27 July and then moved to a health resort in a Minsk outskirt. Each of them reportedly had a small carry on luggage and a total of three big, heavy suitcases per the group.
Belarus' Investigative Committee has launched a probe into the arrested individuals, according to the report.
The Belarusian presidential election is scheduled to take place on 9 August.
The campaign has ignited mass protests Belarus-wide after two prominent opposition candidates — banker Viktor Babariko and diplomat Valery Tsepkalo — were banned from running. The five officially registered candidates include incumbent president Aleksander Lukashenko, who is running for the sixth consecutive term atop 26 years of previous presidential service.