Washington (CNN) -- Leading American Muslims on Wednesday strongly criticized this week's planned congressional hearing into the alleged radicalization of members of their community, calling it an unfair attack on loyal citizens and a dangerous break from the traditional U.S. embrace of tolerance and pluralism. 

Rep. Peter King, the chairman of the House Homeland Security Committee, has said Thursday's hearing is necessary to explore the extent to which al Qaeda is trying to influence and indoctrinate U.S. Muslims, among other things. But his plans have created an uproar, with critics accusing Republican leaders of bigotry and comparing the hearings to Sen. Joseph McCarthy's allegations of Communist infiltration in the early years of the Cold War. 

American Muslim leaders have also taken issue with King's assertion that they haven't sufficiently cooperated with law enforcement officials, and dismissed his claim that the overwhelming majority of mosques are run by extremist imams. Such claims are "demonstrably false," said Nihad Awad, executive director of the Council on American-Islamic Relations (CAIR). 

"Except for a tiny minority," extremists have found "no fertile ground in America," he said. He said King is engaged in "fear-mongering," and called the New York Republican "unfit" to head the Homeland Security Committee. 

"We are not in denial as a community that something is going on, that there are bad actors in every community," said Imam Johari Abdul-Malik, a member of the Council of Muslim Organizations. King is "onto something, but he is going in the wrong direction." 

And Attorney General Eric Holder weighed in as well, disputing King's premise that Islamic leaders haven't done enough to help police during a news conference Wednesday afternoon. 
What does he say of these claims?
Such claims are "demonstrably false," said Nihad Awad