A 22-year-old man who admitted he tried to detonate what he thought was a bomb outside an Army post in Kansas to aid the Islamic State group was sentenced to 30 years in federal prison.

John T. Booker Jr., of Topeka, was sentenced Monday in federal court in Kansas City, Kansas. He pleaded guilty in February to attempting to use a weapon of mass destruction and attempting to destroy government property by fire or explosion.

Booker admitted he tried to set off a 1,000-pound bomb outside Fort Riley, about 60 miles west of Topeka. He was arrested near the post in April 2015 as he was trying to arm the device, which was inert.

He plotted the bombing with two contacts, who were actually confidential FBI sources.