Fox News canceled an interview with Joan Rivers after she called her "stupid and a threat". She blames Sarah Palin for the Tucson shooting, when six people were shot dead.

Rivers made these comments in a TMZ interview when asked whether Sarah Palin should be president of the United States.

She said "I think Sarah Palin is an amazing woman. I think she represents everything strong a woman can be, and I think she should go someplace – to another planet – to show them, and get out of our face."

She went on to say that Palin should be blamed for the attack in Arizona.

"They're right to blame Sarah for the shootings. Go look at her website. This woman is encouraging sandbaggers to reload ... this woman is just stupid and a threat," she said.

Speaking to CNN she said that just after the interview her agent received a call canceling her scheduled appearance on Fox and Friends.

She explained "We got called...So now we call it Fox and Former Friends. They said to our PR lady it was because of what we said about Miss Palin."

Rivers then tweeted "Outcome: DON'T PISS OFF SARAH PALIN. She's apparently 'very powerful', and is obviously still smarting from the end of her reality show."

Fox has claimed that her appearance was canceled due to the "volume of news topics". The news topics included National Penguin Awareness Day, and an assessment of the Aerosmith frontman Steven Tyler's performance as a judge on American Idol. Fox said that she should have been rescheduled but was mistakenly canceled.