The High Fidelity star made the barbed comments on his Twitter.com blog after he was asked his opinion on the proposal to build a mosque at Ground Zero, the site of the former World Trade Center in New York.
He wrote, "I am for a satanic death cult centre at Fox News HQ and outside the offices of (former U.S. Representatives) Dick Armey and Newt Gingrich - and all the GOP (Grand Old Party/Republican Party) welfare freaks."
But his remarks have sparked fury at the news channel, prompting a scathing article on its website and damning comments from behavioural experts.
Psychiatrist Dr. Carole Lieberman tells Fox411, "His provocative tweets could easily incite a rabid fan to commit violent acts against Fox News headquarters and others he names. Fans could not only be influenced because of their devotion to Cusack, the man, but also because of their love for one of the characters he plays."