According to police, a man started stabbing people at a supermarket in New Zealand on Monday, injuring five people, three of whom were seriously injured.

After the incident at a Countdown store in Dunedin, police said a suspect had been arrested and taken into custody. Two store employees were among the injured.

People in the store at the time described it as a chaotic scene, with people screaming and running for the exits. Some brave shoppers, according to reports, attempted to stop the man and tie him down.

The motive for the attack has not been determined, according to Prime Minister Jacinda Ardern, but police have no proof that it was domestic terrorism.

“It goes without saying that such an attack is deeply troubling, and I do want to note the very early accounts of brave bystander actions taken to defend those around them,” Ardern said. “Our hearts go out to anyone who has been affected by this attack.”

Five people were admitted to Dunedin Hospital with stab wounds or similar injuries, according to Ardern.

Three of the injured were admitted to the intensive care unit, a fourth stayed in the hospital's general ward, and a fifth was treated and released, according to health officials.

“The events in our Dunedin Central Store this afternoon have shaken and saddened us,” Countdown said in a statement. “Right now, our top priority is caring for our wounded teammates and our whole family in the aftermath of this traumatic incident. We are very disappointed that customers who attempted to assist our team members were also hurt.”

More information about the incident will be released later Monday, according to police.