A dispute between Moscow and Minsk over the detention of more than 30 men who Belarus accused of being Russian mercenaries deepened on Saturday, as the two sides contradicted each other about the group’s plans, EDNews.net reports citing Reuters.

The arrests this week, shortly before an Aug. 9 presidential election in Belarus, could further strain relations between Minsk and its traditional ally Russia, which soured after the neighbours failed to agree on an oil supply contract for this year.

Russia said on Thursday that the men, who it described as employees of a private security firm, had stayed in Belarus after missing their connecting flight to Istanbul.

President Alexander Lukashenko cast doubt on this version on Saturday.

“There was no Istanbul... It’s clear that the group has had another goals. It is the task of the investigation to find out about those goals”, he said, according to state news agency Belta, after hearing reports from the heads of state security and investigation committee.

He said there had been no agreement with Russia for the men to be in the country, while adding that Belarus is open to cooperate with Russia on the issue.

Belarusian authorities said earlier this week that the men were arrested after Minsk received information that more than 200 fighters had entered the country to destablise it.

On Friday, Alexander Agafonov, the head of the Belarusian investigative group that is handling the case, said that the men - some of whom were wearing army fatigues - had no plans to fly further to Istanbul and said they had given “contradictory accounts” about the purpose of their stay in Belarus.

He was quoted as saying that 11 of the arrested men had told authorities they planned to fly on to Venezuela, 15 - to Turkey, two - to Cuba and one to Syria. Another said he did not know his destination, while three refused to make a statement.