Roger Ailes, the head of Rupert Murdoch's Fox News cable channel, was forced to back down on Thursday after describing America's National Public Radio staff as "Nazis".

In an interview, Ailes attacked NPR's management for its dismissal of commentator Juan Williams over remarks about Muslims and terrorism while appearing on Fox News. Ailes told the Daily Beast website:

They are, of course, Nazis. They have a kind of Nazi attitude. They are the left wing of Nazism. These guys don't want any other point of view. They don't even feel guilty using tax dollars to spout their propaganda.

Hours after the interview appeared, setting off a flurry of controversy, Ailes was quick to apologise by writing a letter to the national director of the Anti-Defamation League: "I was of course ad-libbing and should not have chosen that word but I was angry at the time because of NPR's willingness to censor Juan Williams for not being liberal enough."



The ADL said it accepted Ailes's apology. But earlier in the interview Ailes had defended Fox News firebrand Glenn Beck's attacks on George Soros by saying that there are "left-wing rabbis who basically don't think that anybody can ever use the word, Holocaust, on the air."

The ADL had previously condemned Beck's remarks about Soros's childhood experience as a Jew in Nazi-occupied Hungary, calling them "completely inappropriate and offensive".

Ailes also attacked Jon Stewart, the host of the highly-rated cable comedy The Daily Show, describing his complaints about the damaging cable news environment as "horseshit", and saying of Stewart:

"He hates conservative views. He hates conservative thoughts. He hates conservative verbiage. He hates conservatives.... He's crazy. If it wasn't polarized, he couldn't make a living. He makes a living by attacking conservatives and stirring up a liberal base against it."

Ailes's remarks about NPR spawned mockery on Twitter as users imagined what popular NPR shows would become under a Nazi regime, using the hashtag #nprgoesnazi.

More sagely, one Twitter user noted: "When you say the NPR is as bad as Nazis, you are also saying Nazis are only as bad as NPR."

Ailes also made a coded attack on Barack Obama, claiming: "He just has a different belief system than most Americans" – a rubric used on Fox News, leading bloggers at New York magazine to note: "Ailes spouted exactly the same rhetoric about President Obama that you hear on his channel." Similarly, Jeff Bercovici at Forbes points out: "It's a commonplace by now at Fox that the President is a socialist."