Several people were killed in a shooting at a Copenhagen shopping centre on Sunday, according to Danish police, who added that they had arrested a 22-year-old Danish male and could not rule out an “act of terrorism.”

“There are several injured, and what we also know now is that there are several dead,” Chief Police Inspector Soren Thomassen told reporters, adding that police had initiated a large search effort around the local Zealand region.

Also read: Copenhagen shopping mall shooting: 22-year-old ‘ethnic Dane’ arrested

Thomassen refused to comment on the suspect’s possible intentions or if he was known to police.

Copenhagen police said officers were dispatched to Field’s mall in the Danish capital late Sunday afternoon following reports of a shooting, and that everyone inside the mall were advised to stay put and await aid.

According to investigators, there was no evidence that other shooters were present.

Also read: Harry Styles ‘shocked’ by Copenhagen mall shooting, sends ‘prayers’ and ‘love’

A spokesperson for the capital’s major hospital, Rigshospitalet, said that a “small group of patients” had arrived for treatment, reported Reuters. The hospital had called in additional personnel, including surgeons and nurses, according to the spokesperson.

Also read: Harry Styles Copenhagen concert to go ahead as planned despite mass shooting near venue

Images from the incident showed highly armed police officers and people fleeing the mall, according to local media. Footage provided by the tabloid Ekstra Bladet revealed one person being taken into an ambulance on a stretcher by rescue workers.

“People first thought it was a thief … Then I suddenly hear shots and threw myself behind the counter inside the store,” Rikke Levandovski, an eyewitness, told broadcaster TV2.

“He is just shooting into the crowd, not up in ceiling or into the floor,” she added.

The massive multi-story retail mall, which features stores, restaurants, and parking, is located around 5 kilometres (3 miles) south of central Copenhagen.

Also read: Copenhagen shooting: Shots fired in mall near Harry Styles’ concert venue, several dead

The incident took place across the street from a venue where Harry Styles was scheduled to perform his ‘Love on Tour’ show. Styles expressed shock and sent out prayers and love to his Danish fans after the incident. His show, which was scheduled to begin at 8 pm local time, was officially cancelled by the direction of local authorities, although a previous report by the PA agency stated that the concert was to go ahead as scheduled.    

The Royal House said late Sunday that an event in Southern Denmark to commemorate the finish of the first three stages of the Tour de France cycling race, hosted by the Danish Crown Prince and attended by Prime Minister Mette Frederiksen, had been cancelled.