The shooting occurred Sunday afternoon at the busy Fields shopping mall
The shooting occurred Sunday afternoon at the busy Fields shopping mall

Danish police said Monday the suspect in a weekend shooting at a Copenhagen mall that left three dead, including two teenagers, was known to mental health services.

"Our suspect is also known among psychiatric services, beyond that I do not wish to comment," Copenhagen police chief Soren Thomassen told a press conference.

Thomassen added that the victims appeared to have been randomly targeted and there was nothing to indicate it was an act of terror.

"Our assessment is that the victims were random, that it isn't motivated by gender or something else," Thomassen said.

The police chief could not yet comment on a motive, but said there seemed to have been preparation ahead of the attack and that he was not aided by anyone else.

"As things stand, it seems he was acting alone," he said of the 22-year-old suspect.

The three killed have been identified as a Danish teenage girl and boy, both aged 17, and a 47-year-old Russian citizen residing in Denmark.

Another four were injured in the shooting: two Danish women, aged 19 and 40, and two Swedish citizens, a 50-year-old man and a 16-year-old woman.

About 20 more were lightly injured in the panicked evacuation after the shooting.

The area around the busy mall was quiet on Monday morning.

Mostly journalists were present in front of the main entrance, behind a security cordon guarded by numerous police officers, according to an AFP correspondent at the scene.

Police confirmed that the suspected shooter was known to the police, "but only peripherally".

They added that they believe videos of the suspect circulating since Sunday evening on social media to be authentic.

In some of the images, the young man can be seen posing with weapons, mimicking suicide gestures and talking about psychiatric medication "that does not work".

Three videos believed to have been posted to YouTube by the suspect were all titled "I don't care".

YouTube and Instagram accounts believed to belong to him were closed overnight, AFP noted.

The shooting occurred Sunday afternoon at the busy Fields shopping mall, located between the city centre and Copenhagen airport.

According to police, the shooter was armed with a rifle, a pistol and a knife, and while the guns were not believed to be illegal, the suspect did not have a license for them.

Witnesses quoted by the Danish media described how the suspect had tried to trick people by saying his weapon was fake to get them to approach.

"He was sufficiently psychopathic to go and hunt people, but he wasn't running," one witness told public broadcaster DR.

Other eyewitnesses told Danish media they had seen more than 100 people rush towards the mall's exit as the first shots were fired.

Prime Minister Mette Frederiksen denounced the "cruel attack" in a statement late Sunday.

"Our beautiful and usually so safe capital was changed in a split second," she said.

The mall was busy because of a planned concert with British artist Harry Styles at the nearby Royal Arena that had sold 13,500 tickets but was cancelled at the last minute.

"We got dressed for the concert we were on our way," Maria Enevoldsen, who had returned to the mall Monday to pick up her car, told AFP.

"Our friend (in the mall) called, asking 'are you OK?' and then we heard gunshots over the phone," she said.

The shooting came just over a week after a gunman opened fire near a gay bar in Oslo in neighbouring Norway, killing two people and wounding 21 others.

In February of 2015, two people were killed and five injured in Copenhagen in a series of Islamist-motivated shootings.