It’s no joke – David Letterman is now terror target No.1.

US Muslims were called upon to cut off Letterman’s tongue and “break his neck” in a chilling post by a suspected terror operative on the al Qaeda online forum Shumoukh al-Islam. The late-night funnyman angered a crazy jihadist bearing the moniker Umar al-Basrawi, “Omar from Basra, Iraq,” because he joked about the deaths of Osama bin Laden and his successor.

In the missive, al-Basrawi said Letterman, a Presbyterian, is Jewish and part of a “Zionist” conspiracy.

“I have seen with my eyes and heard with my ears one of the scum of the Jews, one of their pigs, mocking the leaders of the mujahedeen,” al-Basrawi wrote Tuesday, according to translation by the Middle East Media Research Institute, a nonprofit that monitors online chatter.

“We pray to Allah to paralyze his tongue, and that the righteous believers will break his neck,” the threat continued.

A source said al-Basrawi is connected to al Qaeda because in order to post on the Shumoukh forum, the terror group must approve of the author.

Letterman, who is on vacation this week, has often goofed on terrorists.

“So [al Qaeda] picked a successor to Osama bin Laden, and his name was Ilyas Kashmiri,” the CBS “Late Show” star said during his opening monologue on June 8. “Well, guess what: He was blown up by an American drone.

“It wasn’t going to work anyway, because they got off to a rocky start with this guy,” Letterman continued. “He botched up the story of Paul Revere.”

The quip referred to when Sarah Palin bungled an explanation of Revere’s role in the Revolutionary War.

Muhammad Ilyas Kashmiri, a one-eyed top al Qaeda operative, was killed June 3.

An NYPD official said the department is aware of the threat, and notified CBS, as well as local police in Westchester, where Letterman lives.

He may receive a police detail when he returns to New York, sources said.

“It depends on how [the threat] resonates,” an official told The Post. “It has to be determined whether it’s gaining a grass-roots movement.”

Al-Basrawi compared Letterman’s fate to the successful hit on activist Rabbi Meir Kahane, who was killed in Brooklyn in 1990.

“Isn’t there among you [a man like] Sayyid Nosair, the Egyptian, who can cut off the tongue of this lousy Jew and silenced him forever, just like his fellow Jew, Kahane?” he wrote.

A spokesman for Letterman declined to comment.

Additional reporting by Michael Blaustein, Josh Margolin and Larry Celona

chuck.bennett@nypost.com

