A number of unidentified “black-clad” individuals are said to have burned down an election tent kiosk belonging to the populist Sweden Democrats party in the city of Gothenburg.

Police say they believe around ten individuals were involved in the attack with Peter Adlersson of the Western Regional Police saying a preliminary investigation into the incident has been initiated, Swedish broadcaster SVT reports.

Fått information att en av de personerna som hjälpte till med släckningen i natt fortfarande ligger på sjukhus. Alla våra tankar går till honom. pic.twitter.com/5Ygfq3YdtA — jörgen fogelklou 🐘 (@fogelklou) August 17, 2018

“There were several tents there and there was a great risk of spreading to the tents as well,” Aldersson added.

The president of the Sweden Democrats in Gothenburg, Jörgen Fogelklou, condemned the attack, saying: “It’s complete idiocy. They have put people’s lives and health at stake.”

“They are completely confused if they think the destruction of this material will make us quiet. The great cost will be paid to Gothenburg taxpayers. We have borrowed this tent from the city of Gothenburg,” Fogelklou continued, adding: “it was no ordinary tent, it was huge with electricity and a floor.”

The local Sweden Democrat leader estimated that the value of the material in the tent kiosk could run up as much as 10,000 Swedish kronor (£856) but said that despite the setback the party would soon replace the damaged campaign materials.

When the polls don't go your way so you just bomb your opponents instead. Far left violence https://t.co/lwfyzlf2sl — Breitbart London (@BreitbartLondon) August 16, 2018

The attack was also strongly condemned by the Swedish Greens, who released a statement saying: “Even though we in the Green Party are far from Sweden Democrats’ policies, we strongly abstain from attempts to threaten, scare or destroy political opponents.”

The attack comes only days after it was revealed that an office of the Italian populist party La Lega led by Matteo Salvini had been bombed in the city of Treviso, with far-left anarchists taking responsibility for the crime.

Following the initial explosion police were able to diffuse an even bigger bomb on the scene which was filled with shrapnel including nails and shards of metal.

Attacks on populist parties have also been encouraged in Germany by the Antifa movement, who released a “riot tourist” terror handbook earlier this year, telling supporters to attack offices of the Alternative for Germany (AfD) party.