MINNEAPOLIS (AP) -- A 20-year-old Minneapolis man accused of attacking two brothers at the Mall of American says he was inspired by the Islamic State

Mahad Abdirahman has pleaded guilty to two counts of first-degree assault for the November knife attack. His plea deal calls for 151/2 years in prison. Sentencing is scheduled for Feb. 16.

Abdirahman said during his Thursday plea hearing that America "will never be safe'' while it's "at war with Islam.''

Investigators say he attacked 19-year-old Alexander Sanchez and 25-year-old John Sanchez while shopping. The brothers suffered serious injuries.

The charging documents don't provide a motive but suggest Abdiraham has had psychological issues. He was charged with stabbing two staffers with a pen last year at an in-patient psychiatric unit. He was acquitted due to mental illness.