Dahir Ahmed Adan, the Somali American named as the perpetrator of the weekend stabbing rampage in Minnesota, was a high-achieving student with no known history of violence.

Adan -- who police said was 20 years old, but community members said was 22 -- was shot and killed by an off-duty policeman after Saturday's attack, which the Islamic State group claimed as the work of one of its "soldiers."

Members of St Cloud's close-knit Somali refugee community expressed shock that one of their own had stabbed 10 people at a mall in the city 80 miles (130 kilometers) northwest of the state capital St Paul.

Adan's father, in an interview with the Minneapolis Star Tribune, said his son was born in Kenya but grew up in the United States. He said he had "no suspicion" of his son having any ties to terrorism.

The younger Adan graduated with honors from a local high school and was attending a nearby university, said local Abdul Kulane.

"He worked part-time as a private security officer," Kulane told a Sunday news conference.

"He was helpful to his family and as far as we know, he never had a violent history, as far as his family and the community can remember. He was a friendly and active community member."

Adam Hammer, a spokesman for St. Cloud State University, told AFP that Adan's "intended" major was information systems.