A man dressed as a security guard walked into a St. Cloud, Minnesota, shopping mall and injured nine people before he was shot and killed by an off-duty police officer on Saturday night. In a statement on Sunday, ISIS claimed responsibility for the attack.

All nine victims — seven men, a woman and a 15-year-old girl — were treated at hospitals for wounds that weren't life-threatening, St. Cloud police Chief Blair Anderson said at a news conference Sunday. Three remain hospitalized. The others were released.

New York Times reporter Rukmini Callimachi tweeted out a copy of an ISIS statement that said a "soldier of the Islamic State" carried out the attack.

The executor of the stabbing attacks in Minnesota yesterday was a soldier of the Islamic State and carried out the operation in response to calls to target the citizens of countries belonging to the crusader coalition.

The FBI joined the investigation of the incident, which it deems a "potential act of terrorism."

The suspect entered the mall around 8 p.m. Saturday and quickly began stabbing people, according to reports. Soon after he started the attack, however, off-duty police officer Jared Falconer confronted the suspect, who wore "a private security uniform." Falconer identified himself as a police officer and told the attacker to stop during a confrontation caught on security footage, St. Cloud mayor Dave Kleis told the media.

The attacker charged at Falconer, who fired his weapon, causing him to fall down, the Guardian reported. He then stood up and fell down three times and was trying to stand again when Falconer fired the fatal shot. According to police, five minutes elapsed between the time of the first 911 call and the suspect's death.

"He clearly prevented additional injuries and potential loss of life," Anderson said. "Officer Falconer was there at the right time and the right place."

Speaking to the media, FBI agent Richard Thornton said, "We are currently investigating this as a potential act of terrorism, and I do say potential. There's a lot we don't know... We don't know whether the subject was in contact with, had connections with, was inspired by a foreign terrorist investigation. That's what the investigation is attempting to ascertain."

According to Anderson, the attacker referred to Allah and asked at least one victim if they were Muslim. He also said that they are still investigating motive. "We will be diligent and get to the bottom of this," he said.

The Associated Press contributed to this report.

From: Esquire US