Grammy-winning Mumford and Sons have boycotted a Swedish music festival over what they call its disgustingly high rate of sexual violence.

The British band headlined Bravalla festival in Norrköping on the weekend, but have vowed not to return after music lovers reported five rapes and a number of sexual assaults.

On their official Facebook page, the band announced it would not be returning to Sweden, adding: 'We're appalled to hear what happened at the Bravalla Festival last weekend...We're gutted by these hideous reports.'

It follows 35 sexual assaults on girls aged between 12 and 17 at the country's Putte i Parken festival in Karlstad Friday and Saturday including Alexandra Larsson, who spoke exclusively to MailOnline.

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Grammy-winning Mumford and Sons have boycotted a Swedish music festival over what they call its disgustingly high rate of sexual violence

A police officer helps with security in the campsite at Bravalla Festival in Norrkoping, Sweden, on Saturday. Swedish police told the media that they are investigating five cases of alleged rape and more than a dozen suspected sexual assaults committed at the Bravalla Festival over last weekend

Melissa Horn performs at the Bravalla music festival in Norrkoping, Sweden which is the biggest music festival in Sweden where Mumford and Sons would later headline

Swedish Prime Minister Stefan Lofven described the situation as 'totally unacceptable' and said that laws on sexual assault would be tightened

The British band headlined Bravalla festival in Norrköping on the weekend, but have vowed not to return after music lovers reported five rapes and a number of sexual assaults

Swedish fans could be waiting a while for the return of Mumford and Sons, who took a stand against the festival and its molesters, saying: 'We're appalled to hear what happened at the Bravalla Festival last weekend.

'Festivals are a celebration of music and people, a place to let go and feel safe doing so.

'We're gutted by these hideous reports.

'We won't play at this festival again until we've had assurances from the police and organisers that they're doing something to combat what appears to be a disgustingly high rate of reported sexual violence.'

The band signed the post off with the letters M, W, B and T - the initials of the groups' members Marcus Mumford, Winston Marshall, Ben Lovett and Ted Dwane.

Several Swedish artists also hit out after the police reports emerged over the weekend.

Zara Larsson, who configured with David Guetta for the official Euro 2016 song, angrily tweeted, 'Damn you who shamelessly rapes a girl in the audience. You deserve to burn in hell. I hate you guys.'

Fy fan för er killar som får tjejer att känna sig osäkra när de går på festival. Jag hatar killar. Hatar hatar hatar. — Zara Larsson (@zaralarsson) July 1, 2016

Fyfan för dig som helt skamlöst våldtar en tjej i publikhavet. Du förtjänar att brinna i helvetet. — Zara Larsson (@zaralarsson) July 1, 2016

Swedish Prime Minister Stefan Lofven described the situation as 'totally unacceptable' and said that laws on sexual assault would be tightened.

'We are in the process of reviewing them,' he 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.'

Police handed out anti-groping bracelets ahead of the festival season in Swedish aimed at raising awareness and quashing sexual harassment, but the efforts were in vein and campaigners are calling for more to be done.

Swedish police press spokesman Thomas Agnevik, who was present at the Bråvalla festival, told The Local: 'I can understand that criticism.

'As long as these serious crimes are happening, of course not enough has been done.

'Nobody should have to go to a concert and leave as a rape victim.'

Alexandra Larsson (pictured) told MailOnline she was molested on Friday night having been looking forward to attending the festival for months

A 17-year-old told MailOnline of her ordeal after a mob of 'foreign youths' sexually assaulted dozens of females at a Swedish music festival.

At least 35 aged between 12 and 17 reported being attacked during the 'Party in the Park' festival in Karlstad, 250 miles from Stockholm in Sweden's Varmland County on Friday and Saturday night.

Some of the alleged victims reported being 'kissed and groped' in scenes similar to the Cologne New Year attacks, in which dozens of women reported being assaulted.

Police say the attacks happened during the 'Party in the Park' festival (pictured) in the city of Karlstad, 250 miles from Stockholm in Sweden's Varmland County on Friday and Saturday night

Alexandra Larsson, who waived her right to anonymity, she was molested on Friday night having been looking forward to attending the festival for months.

She said: 'Everything was okay at the beginning of the evening. But things got out of hand during the last concert with John de Sohn that started at midnight.

'At first we were pushed right up against the stage by the massive crowd. Everyone around us behaved really badly and my friends told a couple of boys to quieten down.

'They were then threatened by the boys who said 'you will die, b***h'. But the verbal abuse was just beginning. It would become much worse.

'We managed to walk away from those boys after a while and started watching the concert. That was when I felt the first touch against my bottom.

'Then someone took the liberty of grabbing my butt really hard. I turned away and said to the group of boys behind us that this was not okay, but I did not know who had done it. After a while, I felt someone running his fingers between my legs touching my genitals. Luckily, I had jeans on me.'

After the harassment, she turned around and said to the group of young men standing next to her that they should stop what they were doing. But everyone around her claimed to be innocent.

About 20 000 visited the festival every day during the three-day festival which was free. The majority of the visitors were teenagers

It then happened again, she said.

'I turned around and screamed right out that 'whoever it was - you're a pig!' I told my friends what had just happened and they were all shocked. Me and my girlfriends decided to leave the concert, because we could not see who it was. It was just a sea of ​​people.'

Ms Larsson described a feeling of powerlessness as the festival she and her friends had been looking forward to was completely destroyed.

'It was creepy. Someone stood around me and groped me and I had no idea who it was. It was sick. We had come there to have fun, but the festival only lasted 20 minutes for us because it was so uncomfortable.

'The groping was at first a bit innocent. Just a touch on the bottom. Something that you can do by mistake in a big crowd of people. But it became worse and worse after that. The one touching me was becoming more and more rough every time.

She said that the boys around them were about 17 or 18-years-old but 'those standing behind me were not from a Swedish background.'

'They were probably immigrants. I hate to say it. But it is the truth,' she said.

'I have reported this to the police, but it feels like a drop in the ocean. I saw girls that came crying from the audience, including an old childhood friend who is two years younger. She cried so much that it broke my heart.

'The same thing had happened to her in front of the stage. A bunch of teenagers hidden in the crowd had grabbed her bottom, breast and genitals .

'I think that at least hundreds were molested at the festival. There are probably loads of unrecorded incidents. Girls who have a low self esteem might think that it is their fault - that perhaps they did something wrong to provoke it. But they are wrong. Nobody gets to touch a woman without her own permission.

At least 35 girls aged between 12 and 17 have reported being sexually assaulted by 'foreign youths' at a Swedish music festival, it has emerged (file picture)

'I have heard of others who had been grabbed during previous festivals. But it was sick being subjected to it myself, especially because it was so rough. It was like a punch in the face that it actually happened.

'I could see crying girls everywhere around me when I left the festival. I don't know if they all had been groped, but most of them probably had been violated in front of the stage.

Ms Larsson said that she was 'strong and could cope with it' but added: 'When a 14-year-old girl who is not as strong becomes a victim, she can be completely destroyed. That is what is so sick. It happens all the time but we can not do anything about it.

'I do not know what to think, it is so wrong. Everyone thinks it's wrong but nothing happens. There are large festivals with several thousand people and these mass incidents create a powerlessness for both the police, security guards and especially for visitors who become victims.

'The perpetrators will be so anonymous in the audience that they will get away with sex crimes. That is the main problem, that the perpetrators get away with it.

'It's not okay. I should be able to go to festivals and have fun like everyone else without being afraid. It is wrong, really wrong, but that's the feeling I have after yesterday. It's damn hard that ordinary people who just want to have fun should have to suffer just because someone thinks it's fun to violate.

She said that she believed the problem was spreading 'because attackers know they will not get caught'.

But she added that police took it 'really seriously' when she reported the incident and is hoping that this will lead to something.

'I will not visit the festival again. It was so uncomfortable, I do not want to risk that happening to me one more evening.

'I talked about this with my father and my three brothers. They were all devastated when they heard about what had happened. Especially my father who told me that normal men know that they are not allowed to touch women who do not want to be touched. He cannot understand what kind of moral guidance these boys must have.'

The touring 'Party in the Park' festival had about 20,000 visitors every day between Thursday and Saturday

The touring festival had about 20,000 visitors every day between Thursday and Saturday.

It was free and the majority of the visitors were teenagers. The bands playing were mostly Swedish and 1980s act 'Europe' were headlining.

Police reported that the perpetrators linked to the assaults were 'young men, who are foreigners'.

They have arrested two boys, both living at a nearby asylum centre for unaccompanied refugee children.

Meanwhile the tabloid Expressen has talked to a concerned mother who said that the security guards' response when her daughter reported that she had been molested was 'that is just something that happens when you are at a festival'.

Her daughter described what happened to her, adding: 'I was standing up and danced when a guy came from behind and held me down and started humping against my body. It was horrible.'

Breitbart reports that the promoter of the Putte i Parken festival said he found the behaviour of his staff unacceptable and that they should lose their security licences.

Up to 24 of the reports related to alleged assaults during the festival while a further 11 happened afterwards, according to Breitbart.

Expressen said one victim had been at the festival with six young friends - five of whom were also molested.

The incidents happened about a week after the Swedish police started its new campaign against groping.