STAVANGER, Norway (AP) — Sweden’s prime minister says Swedish police must get better at investigating sex crimes after a series of assaults were reported at one of the country’s biggest music festivals.

Organizers of the Bravalla festival in Norrkoping, which hosted 45,000 people in southern Sweden, have called off next year’s event following a rape allegation by a young woman. In addition, three more allegations of sexual assault were reported overnight, bringing the total number of reported sexual assaults to 23.

Prime Minister Stefan Lofven told a news conference Sunday that he was upset that young women who wanted to listen to music should be “exposed to this.” He said “these are disgusting acts. We must stop this.”

Lofven said Sweden needed better policing, more video surveillance and swifter justice for perpetrators.