Security forces in Belarus said they arrested 32 Russian “mercenaries” near the capital city of Minsk on Wednesday for allegedly trying to disrupt the nation’s August 9 presidential elections, Voice of America (VOA) reported Thursday.

State news agency BelTA reported that security forces detained 32 alleged foreign fighters from Russia’s private military contractor Wagner Group on Wednesday night at a health resort outside Minsk. According to BelTA, Belarus security forces said they made the arrests after receiving information from an undisclosed source that over 200 Russian military contractors arrived in Belarus last Friday to “destabilize the situation in the country ahead of the election.”

Belarusian state news agency Belsat claimed that security forces discovered the alleged Russian contractors at the resort because they stood out for their unusual behavior.

“They did not drink alcohol or visit entertainment facilities and kept to themselves to maintain a low profile,” the report noted, adding that this was “atypical behavior for Russian tourists.”

Video of the raid aired by the state-run Belarus-1 TV channel showed Belarus security forces raiding the men’s hotel rooms overnight and detaining the men, some in their underwear. In the footage, guns and ammunition are seen scattered among the men’s belongings.

VOA reported that Belarus’s KGB issued a statement “identifying the men as part of the Wagner Group,” allegedly controlled by an ally of Russian President Vladimir Putin. The Wagner Group is believed to promote the Kremlin’s interests in Ukraine, Syria, Libya, and other parts of Africa.

Zahar Prilepin, a former pro-Russian rebel fighter in east Ukraine, told Russian news site URA.ru on Wednesday that he recognized some of the men detained in the Belarus state TV footage as Wagner mercenaries with whom he has previously worked.

“There are two or three fighters from my battalion there [in the footage],” Prilepin said.

On Friday, Kremlin spokesman Dmitry Peskov seemingly confirmed that the men detained by Belarus authorities on Wednesday were Russian nationals. Speaking to journalists, Peskov said that the “groundless detention of Russian citizens does not quite fit the parameters of allied relations.”

“We hope that in the very near future this incident will be explained by our Belarusian allies and that the citizens will be released,” he added. Peskov described the men as “employees of a private security company” who were temporarily in Belarus en route to Istanbul.

Moscow has officially denied any involvement in any alleged plot to interfere in Belarus’s election. Russian President Vladimir Putin’s spokesman Dmitry Peskov said claims that “organizations from Russia are sending some people to destabilize the situation in Belarus” were “nothing but insinuations,” according to the newspaper.

Though officially allies, the relationship between Moscow and Minsk has become increasingly strained in recent years, reportedly over Lukashenko’s alleged resistance to the Kremlin’s desire to reunify Belarus with Russia as part of a supra-state.

Wednesday’s arrests came as Belarus enters the final days of its contentious election season ahead of an August 9 presidential vote. Dictator Alexander Lukashenko has ruled over Belarus as president since 1994, when the office was established after the fall of the Soviet Union. In the run-up to the presidential election, Lukashenko has detained multiple opposition candidates, whose wives have replaced them on the ballot.

The Belarus election commission gathered the presidential election’s remaining candidates for a meeting on Thursday to announce that the government would increase security measures at campaign rallies and mass gatherings in light of Wednesday’s arrests of alleged election agitators.

On Thursday, Belarus’ Investigative Committee said that the group of Russians detained Wednesday along with two former presidential candidates would face joint criminal charges for allegedly “preparing mass disorder,” a crime with a punishment of up to eight years in prison in Belarus, Radio Free Europe/Radio Liberty reported.

One of the people implicated in the investigation is Sergei Tikhanovsky, who was detained by state authorities while campaigning as an opposition candidate in this year’s election. His wife, Svetlana Tikhanovskaya, replaced him on the ballot after his detention and has denied any involvement with the incident.

Tikhanovskaya, a 37-year-old mother of two, has emerged as Lukashenko’s staunchest opposition in the final days before the election. The unlikely presidential candidate has gained a massive following, drawing tens of thousands of supporters to a rally in Minsk on Thursday despite the government’s increasing crackdown on the opposition. Held in a Minsk public square, the gathering “appeared to be the largest opposition protest in the ex-Soviet country in a decade,” an Agence France-Presse journalist covering the rally told the Moscow Times.