Police and witnesses said the man, wearing a private security company uniform, made a reference to Allah and asked someone if he was a Muslim before striking.
An ISIS-affiliated news outlet claimed that the attacker was “a soldier of the Islamic State.”
“He carried out the operation in response to calls to target the citizens of countries belonging to the crusader coalition,” read a statement from the organisation’s Amaq news agency.
The attacker was shot dead by a police officer.
“An armed suspect entered the Crossroads Mall. That individual made some references to Allah, and we have confirmed that he asked at least one person if they were Muslim before he assaulted them,” Blair Anderson, a senior police officer, told reporters.
Anderson later told CNN that: “We still don’t have anything substantive that would suggest anything more than what we know already, which is this was a lone attacker… And right now, we’re trying to get to the bottom of his motivations.”
St. Cloud Mayor Dave Kleis said three people remain hospitalised, including one person who is in a life-threatening condition.
Among the injured were a 15-year-old girl, a 50-year-old woman and seven men ages 20 to 53.
Ashley Bayne, an employee of JCPenney at the mall, was visiting a coworker at the time of the incident.
“All of sudden chaos just broke out,” she told CNN’s Nick Valencia on Sunday. “There was a bunch of people running into the JCPenney mall entrance, and they were just screaming that someone was going around the mall stabbing people, and that there was blood everywhere. It was just honestly a really scary experience.”
Bayne said she ran out to the parking lot and took off in her car.
The stabbings occurred in multiple locations inside the mall, including the common area and in several stores. The mall has security teams on site but they are not armed.
While the attacker was not identified, authorities said he had had three previous encounters with police.
Anderson said most of the encounters were for minor traffic violation.
Twenty-nine people were injured in two separate bomb attacks in New York.
Extremist groups, which have carried out coordinated assault across Europe, has repeatedly threatened to attack the US.