MINNEAPOLIS -- Garrison Keillor, the former host of "A Prairie Home Companion," says he's been fired by Minnesota Public Radio (MPR) over allegations of improper behavior.

Keillor told the Associated Press of his firing in an email. In a follow-up statement, he says he was fired over "a story that I think is more interesting and more complicated than the version MPR heard." He didn't give details of the allegation.

MPR confirmed Keillor had been fired, saying it learned of "allegations of his inappropriate behavior with an individual who worked with him" and doesn't know of any other similar allegations. The station said it was ending its contracts with Keillor while an internal investigation continues.

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Keillor, 75, retired as host of his long-running public radio variety show in 2016. His hand-picked successor, mandolinist Chris Thile, is in his second season as "Prairie Home" host.

The statement came shortly after Keillor, an avowed Democrat, wrote an op-ed for the Washington Post published Wednesday that the notion that Minnesota Sen. Al Franken should resign for his own misbehavior is "pure absurdity."

Keillor started his Saturday evening show in 1974, featuring tales of his fictional Minnesota hometown of Lake Wobegon -- "where all the women are strong, all the men are good-looking, and all the children are above average." The show featured musical acts, folksy humor, parody ads for fake products such as Powdermilk Biscuits and the centerpiece, Keillor delivering a seemingly off-the-cuff monologue, "The News From Lake Wobegon," in his rich baritone voice.

Keillor bowed out with a final show at the Hollywood Bowl in July 2016 and turned the show over to Thile, a mandolinist and frequent "Prairie Home" guest musician. Keillor went on a 28-city bus tour this summer, vowing it would be his last tour, but he continues on the road with solo shows.

Keillor still produces the radio show, "The Writer's Almanac," for syndication, and is finishing a Lake Wobegon screenplay and a memoir about growing up in Minnesota.