It seems even death threats can't dull David Letterman's sense of humor. On Monday night's 'Late Show,' Letterman fired off a salvo of jokes in response to the internet jihadist who recently called for the late-night host's tongue to be cut out.

Last week, a post on the Shumukh al-Islam forum demanded that Letterman be punished for joking about Al Qaeda leader Illyas Kashmiri, who was killed in June during a drone strike in Pakistan. The anti-semitic rant exhorted extremists to remove Letterman's tongue and "shut it forever."

Letterman wasted no time addressing the threat. "We have a great audience night in and night out, but, honestly, tonight you mean a lot to me," he said at the start of his monologue. "You people are more than an audience tonight, really. You're more like a human shield."

More jokes on the subject followed. Letterman even quipped that late-night rival Jay Leno was behind the threat. "And so now, State Department authorities are looking into this. They're not taking this lightly. They're looking into it. They're questioning, they're interrogating, there's an electronic trail -- but everybody knows it's Leno," he said.

Watch the monologue below:

[Late Show With David Letterman]