A federal grand jury has handed down a three-count indictment charging a 20-year-old Kansas man with trying to carry out a suicide attack at Fort Riley.

Prosecutors say John T. Booker Jr. of Topeka was arrested Friday while trying to arm what he thought was a 1,000-pound bomb inside a van near the Army post an hour west of Topeka.

A federal grand jury in Kansas City, Kansas, on Thursday indicted Booker for attempting to use a weapon of mass destruction and other charges, including attempting to provide material support to the Islamic State group.

Prosecutors say Booker told undercover FBI informants that he wanted to kill Americans and engage in violent jihad on behalf of the group.