(CNN) -- A jihadist website is urging its American followers to kill comedian David Letterman, saying his tongue deserves to be cut over his remarks about a terror leader, an online intelligence group said. The writer posted the death threat after he got upset by a Letterman joke about an al Qaeda leader killed in Pakistan, according to SITE intelligence group, which monitors and translates online terror activity. Ilyas Kashmiri, described as al Qaeda's "military brain," died in a drone strike in June, his jihadist group said at the time. Letterman cracked jokes about the killing, and dragged his finger across his neck to show "the way of the slaughter,"  the message on the jihadist site said.
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NEW: Letterman's fans support him online, with one saying, "Keep doing what you do Dave"
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NEW: An expert notes jihadists' "obsession with the United States and the West"
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A group says the death threat comes after Letterman jokes about a terror leader's death
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The death threat urges jihadist followers to cut off Letterman's tongue and "shut it forever"
As such, a specific threat -- like the one targeting @placeholder -- could be viewed as encouraging others to act.