Fox News' Bill O'Reilly says his threat have a reporter beheaded is a joke. But The Washington Post columnist who is target of those threats thinks it is no laughing matter.

On the Thursday edition of The O'Reilly Factor, O'Reilly took exception to the way The Washington Post's Dana Milbank characterized Fox News' election coverage.

"To be fair and balanced, Fox brought in a nominal Democrat, pollster Doug Schoen," wrote Milbank. "'This is a complete repudiation of the Democratic Party,' [Schoen] proclaimed."

"He said there were no Democrats except for Schoen on," O'Reilly grumbled. "It was an outright lie."

"Does sharia law say we can behead Dana Milbank?" he asked his 5.5 million viewers. "That was a joke," O'Reilly added.

"Hilarious!" declared Milbank. "Decapitation jokes just slay me, and this one had all the more hilarity because the topic of journalist beheadings brings to mind my late friend and colleague Danny Pearl, who replaced me in the Wall Street Journal's London bureau and later was murdered in Pakistan by people who thought sharia justified it."

The following night, one of O'Reilly's viewers complained about the beheading reference.

"I thought the joke about whether sharia law would allow the beheading of the Washington Post guy was completely inappropriate," the viewer wrote.

But O'Reilly was unrepentant. "Well, let me break this to you gently, Heidi. If Dana Milbank did in Iran what he does in Washington, he'd be hummus."

"What was he trying to say?" Milbank asked. "That America would be better if it were more like Iran?"

At one point on Thursday's show, O'Reilly told Fox News host Megyn Kelly, "We should go beat him up."

Kelly pushed back by saying, "When somebody missteps, especially when it comes to any sort of speech or expression of opinion, the answer is to have more speech and opinion."

"I'm not trying to muzzle the guy," O'Reilly countered.

"True," Milbank agreed in his column. "You don't need a muzzle if your head has been cut off."

"I don't believe O'Reilly really wants to sever my head, but if only one of his millions of viewers interprets his message otherwise, that's still a problem for me," the columnist conclued.

And maybe Milbank has reason to worry. Dr. George Tiller, an abortion provider, was murdered after years of O'Reilly calling him a "baby killer."

Another Fox News host, Glenn Beck, allegedly has been an inspiration for a police killing, threats on a senator's life and a California shooter.

This video is from Fox News' The O'Reilly Factor, broadcast Nov. 4, 2010.