At least three people were killed and four others injured in a shooting attack at a shopping center in Copenhagen, the capital of Denmark, and one suspect was arrested, local police said.

The three victims are, respectively, a 17-year-old Danish man, a 17-year-old Danish woman and a 47-year-old Russian living in Denmark, local police said at a press conference Monday morning, adding that two Danish and two Swedes are seriously injured. 

Local police also said there is "no indication that shooting was an act of terror. "

The police received reports of shootings in the Field's shopping center in the Amager area of southern Copenhagen around 5:30 p.m., Soren Thomassen, Copenhagen's chief police inspector, said at a press conference on Sunday evening.

Thomassen said a 22-year-old Dane was arrested outside the shopping mall shortly after police arrived.

The police have launched a massive manhunt operation in the whole Zealand region, the southernmost administrative region of Denmark.

The municipality of Copenhagen has also activated its emergency response after the incident.

"The crisis response team in the Copenhagen municipality has been called in. We are ready to help if the Copenhagen Police requests it," said Copenhagen Mayor Sophie Haestorp Andersen.

The attack rocked Denmark at the end of an otherwise joyful week, just after it hosted the first three stages of the Tour de France cycle race, an event that had sent thousands of cheering Danes into streets across the country.

"Denmark was hit by a cruel attack on Sunday night. Several were killed. Even more wounded. Innocent families shopping or eating out. Children, adolescents and adults," Prime Minister Mette Frederiksen said in a statement late on Sunday.

"Our beautiful and usually so safe capital was changed in a split second," she said. "I want to encourage the Danes to stand together and support each other in this difficult time."

A spokesperson said the capital's main hospital, Rigshospitalet, had received a "small group of patients" for treatment and had called in extra doctors and nurses.

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.

The attack follows a deadly shooting in neighboring Norway last week, in which two people were killed by a lone shooter in the capital Oslo.

Denmark last saw a militant attack in 2015, when two people were killed and six police officers wounded when a lone gunman shot and killed a man outside a culture center hosting a debate on freedom of speech and later killed a person outside a Jewish synagogue in central Copenhagen. That gunman was killed in a shoot-out with the police.

"Our thoughts and deepest sympathy are with the victims, their relatives and all those affected by the tragedy," Denmark's Queen Margrethe and the Crown Prince couple said in a statement.

(With input from agencies)