LJUBLJANA, Slovenia — Slovenian police said Tuesday they have launched an investigation after video footage and photos appeared on social media of a group of armed, masked men led by a right-wing former presidential candidate.

Interior Minister Vensa Gyorkos Znidar said authorities will not tolerate the existence of any parallel armed groups in Slovenia.

The video showing several dozen masked men training in a field in military-like outfits and holding axes and rifles has sparked concerns in the small European Union nation.

Nationalist politician Andrej Sisko has confirmed the existence of the group, which he described as guards of the Stajerska region, in the northeast of the country.

Sisko, who won some 2 percent of votes in last year's presidential election, is known for his nationalist and anti-immigrant stance. His United Slovenia Movement party didn't make it to parliament in June's election.

Sisko told the official STA news agency that his group was not a paramilitary unit, but a "volunteer defense group of free men."

Top officials have condemned the existence of the group. President Borut Pahor said it was "completely unacceptable," while Prime Minister-designate Marjan Sarec tweeted that any armed group outside Slovenia's security forces "undermines the constitutional and legal order."