Sweden’s largest music festival has been cancelled next year due to reports of rape and sexual assaults at the event over the weekend.

Allegations of rape and sexual assault at several music festivals in recent years have sparked outrage in Sweden.

Police in the south-eastern district of Östergötland, where the annual Bråvalla festival took place, said they received four rape and 23 sexual assault reports between Thursday and Sunday.

One woman said she was forced to have sex with a man after changing her mind.

“Certain men … apparently cannot behave. It’s a shame. We have therefore decided to cancel Bråvalla 2018,” the festival’s organisers said .

The chief police investigator, Martin Hedberg, said: “Many reports [of sexual assault] come after they’ve happened so there are weak descriptions [of the suspects] and nothing more to go on.”

Last year, local media reported that five women were allegedly raped at the four-day festival, attended by thousands of people each year.

The prime minister condemned the incidents and called for more surveillance at festivals.

“This is so disgusting. These are obnoxious acts by deplorable men,” Stefan Löfven told the Swedish daily Expressen in televised comments on Sunday. “This must stop”

The prime minister said the government was in talks with the police about increasing surveillance at such events.

Last year, police were accused of withholding information about about alleged sexual assaults against women by young immigrants at a Stockholm summer music festival in 2014 and 2015.

But the Swedish prosecutor’s office later dropped an investigation into the case.

This year’s Bråvalla festival continued as planned despite the alleged assaults and ended on Saturday with performances by the Killers, Prophets of Rage and Dutch DJ Martin Garrix.

FKP Scorpio, the German owner of the Bråvalla festival, blamed last year’s incidents on a drop in ticket sales.

The festival sold about 45,000 tickets this year compared with 52,000 in 2016.

“It stopped being about music and became almost completely about crime and violence,” said Folkert Koopmans, chief executive of FKP Scorpio.