ST. LOUIS -- A man has been sentenced to two and a half years in prison for threatening to kill President Barack Obama.

Federal prosecutors say 33-year-old Josh McCallum of Neosho, Missouri, was sentenced Tuesday in US District Court in St. Louis. He pleaded guilty in May.

McCallum was already incarcerated at the Northeast Correctional Center in Bowling Green in August 2009 when he mailed a threatening letter to the White House that read in part, "The president needs to be shot."

McCallum has been held at the Bowling Green prison since 1999 on tampering and burglary charges. He will serve the federal sentence after his state charges expire in 2018.

His attorney, Felicia Jones, did not respond to interview requests. (AP)