Image copyright EPA Image caption Marcus Mumford: 'We are gutted by these hideous reports'

Mumford and Sons say they will boycott a Swedish music festival after reports emerged that 17 women were sexually assaulted at the event last weekend.

Authorities received five reports of rape and 12 of sexual assault during Bravalla, Sweden's biggest festival.

"We're appalled to hear what happened," wrote Mumford and Sons on Facebook.

"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."

They added: "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."

Swedish pop star Zara Larsson also wrote a series of furious tweets after hearing a woman had been raped while she played the festival.

"You deserve to burn in hell," she wrote. "[Damn] you for making girls feel insecure when they go to a festival. I hate guys. Hate hate hate.

"How am I supposed to take it seriously when you say 'not all men', 'I'm a nice guy, I don't rape'? Where do all the 'nice guys' go when girls are raped? Are you too busy telling women how nice you are?"

Image copyright Getty Images Image caption Zara Larsson: 'It's hard to feel insecure about a festival where you just wanna go to have fun and enjoy.'

Swedish Prime Minister Stefan Lofven described the attacks on female audience-members as "totally unacceptable" and said laws on sexual assault would be tightened.

"In addition, it is also important that we continue to make sure the police, prosecutors and other authorities get better at investigating these crimes so that we make sure we actually convict the perpetrators."

Numerous accounts of sexual violence were also reported at Sweden's Putte I Parken festival, which took place between 30 June and 2 July.

According to the Associated Press, 32 reports of "attacks by boys or young men" against female attendees were registered at the event, with the youngest victim just 12 years old. Police have identified seven men whom they hope to question about the attacks.

The problem is not isolated to Sweden. Three cases of sexual assault were reported at the 2015 Glastonbury festival, while a man was arrested for raping a 21-year-old woman at last year's V Festival in Essex.

Last week in Denmark, where the annual week-long Roskilde rock festival took place, police said they had reports of five cases of alleged rape or sexual assault.

Police officer Carsten Andersen described the figure as "nothing out of the ordinary at such a big event, although every single case is too much".

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