The epidemic of mass sexual assaults by so-called “foreign men” at Swedish music festivals continues, with reports of nearly 40 assaults, including five rapes, at the country’s largest festival.

The shocking revelations come just over a week after 32 similar sexual attacks were reported at ‘Putte i Parken’ (Party in the Park) music festival in Karlstad.

This weekend, at the Bravalla Festival in Norrkoping, about 100 miles from Stockholm, one anonymous 15-year-old girl told Expressen how she and six friends had been molested by “foreign youths”.

Alexandra Larsson, 17, told MailOnline that the attackers were “not from a Swedish background”, adding: “They were probably immigrants. I hate to say it. But it is the truth.”

Police confirmed that they had identified but not detained the perpetrators, yet resolutely refused to comment on reports that migrants or foreigners were involved.

Police spokesman Thomas Agnevik, who was at the festival, said: “I won’t comment about their background but they are young boys aged between 15 and 25.”

The force has now confirmed that there has been five alleged rapes, 12 sexual molestations and 32 reports of sexual assault.

Inspector Leif Nystrom, of the Karlstad Police Department, added: “These were reports of women being touched in unwanted places, such as on their breasts and on their bottoms and inside their underwear.

“We want to catch the suspects because we need to talk to them… The number of such cases has increased slightly since last year, but I’m really not sure if this is a common problem at festivals.”

Mumford and Sons, the Grammy award-winning British band who headlined the event, have promised to boycott the festival in future unless authorities do more to tackle the “hideous” and “disgustingly high rate of reported sexual violence”.

The attackers at the ‘Party in the Park’ music festival in Karlstad last week were also identified as “foreign” and preyed on their victims in similar way to those at the festival in Norrkoping, and even the New Year’s Eve attacks by ‘asylum seekers’ in Cologne, Germany.

Sweden has experienced such attacks at festivals for years now, with dozens of girls assaulted by “Afghan youths” at a teenage festival in Stockholm in 2015.

Police were accused of a “cover-up” as they initially claimed there were “relatively few crimes”, with the attacks only making it into the media after the Cologne scandal broke.

Swedish authorities have been repeatedly slammed for their inaction. In an effort to look proactive they handed out wristbands with “don’t grope” written on them at the Bravalla festival. Several girls who were assaulted were wearing the wristband, which did not offer them much protection.

Last month, an official report by Swedish police into the migrant sex attack phenomenon blamed “Nordic alcohol culture” and the “non-traditional gender roles” of European women for the growing problem.

Migrants, the police said, might not be able to “handle the alcohol”, simply feel “horny”, have “ignorance of the consequences for the girls”, “have misplaced feelings”, be “expressing anger in this way”, or be acting due to “peer pressure”.

Forty years after the nation’s parliament decided to transform Sweden with mass immigration into a multicultural society, violent crime has increased by 300 per cent and rapes by 1,472 per cent.

Now, Sweden has the worst rates of physical and sexual violence committed against women in the European Union (EU), according to a survey by the EU’s rights agency.

Following the multiple instances of mass sex attacks over the past two weeks, the Swedish prime minister described the situation as “totally unacceptable” and said laws on sexual assault would be tightened.

“We are in the process of reviewing them,” Stefan Löfven said in a speech at a political seminar. “It’s also important that we continue to ensure that police, prosecutors and other officials are better equipped to investigate such crimes and actually catch the perpetrators.”