A “large-scale” police manhunt is continuing after a deadly shooting at a rave in northern Switzerland left an Italian woman dead and several injured early on Sunday.

“We are currently in the middle of a large-scale operation in progress,” said Michael Leupold, commander of the Aargau regional police, at a press conference on Sunday evening.

Until the perpetrators have been identified and stopped, “there is no end to this large-scale operation in sight,” he added.

A 22-year-old Italian woman was killed by one or more shots shortly after the end of the event in Aarau, about 40 kilometres west of Zurich.

Investigators currently believe the young woman, who was resident in Switzerland, was a random victim.

Five other participants in the rave event were injured, though none were in a life-threatening condition by the evening.

Authorities are currently working with three equally weighted hypotheses, Leupold added. The shooting could be a terrorist act, a rampage or a settling of scores in criminal circles.

Police said traces of two different types of weapons were found after shots were fired.

The event, which ran from Saturday afternoon until 2 am on Sunday (0000 GMT), had already ended and only around 100 people were believed to have remained at the venue, the spokesman said.

Police received the first emergency calls at around 2:30 am and deployed a large number of officers to the scene.

The area remained extensively cordoned off on Sunday, although police said this was primarily to preserve evidence rather than because of an immediate danger to the public.

Authorities appealed for witnesses to submit video and photographic material.

Thousands expected at rave

Organizers had expected around 3,500 people at the Aarauer Rave, a long-established event held on the grounds of the Aargau Racing Club.

The event had been promoted in advance as the “largest rave in north-western Switzerland.”

The racing club expressed its condolences to the victims’ families.

The party “was overshadowed by a serious incident,” the club said in a statement, adding that emergency services had been immediately alerted.

Meloni offers ‘deepest condolences’

After the Italian Foreign Ministry confirmed the victim was an Italian national, Prime Minister Giorgia Meloni offered her “deepest condolences” to the woman’s family in a post on X.

She said her thoughts were with the woman’s relatives, the injured and all those affected by the incident.

Meloni said she was following developments closely and “trusting in the work of the Swiss authorities to shed full light on what happened and identify those responsible.”

Witnesses thought shots were fireworks

Several witnesses told Swiss newspaper Blick that revellers initially mistook the burst of gunfire for fireworks.

One woman said someone then shouted “Everybody down!” and her group hid beneath the DJ booth. A woman was struck by a bullet, she said.

“It was terrible,” the witness told Blick.

Those still at the rave were taken by police to a nearby gymnasium.

DJ Tekibo, who was performing at the event, described what had happened as “absolutely heartbreaking” in an Instagram story.

“Techno and raves are supposed to be a place for freedom and safety,” he wrote, adding that he had “lost an important friend” and would withdraw from performing for a period of time.

Police across the border in Germany were also involved in the wider search operation following the shooting.

A spokesman for police in Freiburg described the cross-border involvement as routine but gave no details of the specific measures being taken.