WASHINGTON - Despite criticism from some politicians and a section of the US news media, the new head of a Congressional panel is pushing ahead with a controversial investigation next month into what he calls a very real threat - the radicalisation of young Muslims by local religious leaders. Congressman Peter King, Republican, was quoted as saying Wednesday that he planned to call mostly Muslim and Arab witnesses to testify in hearings on the threat of homegrown terrorism. He told The New York Times he would rely on them to make his case that American Muslim leaders have failed to cooperate with law enforcement officials in the effort to disrupt terrorist plots - a claim that was rebutted in recent reports by counter-terrorism experts and in a forum on Capitol Hill on Monday. I believe it will have more of an impact on the American people if they see people who are of the Muslim faith and Arab descent testifying, King was quoted as saying. The hearings, which King said would start the week of March 7, have provoked an uproar from both the left and the right. The left has accused King of embarking on a witch-hunt. The right has accused him of capitulation for calling Muslims like Congressman Keith Ellison, a Democrat who is a Muslim, to testify while denying a platform to critics of extremism like Steven Emerson, Frank Gaffney, Daniel Pipes and Robert Spencer. As the hearings approach, the reaction from Muslim groups - initially outraged - has evolved into efforts to get King to enlarge the scope of the hearings beyond Muslims. They want to use the forum to reinforce the notion that the potential for terrorist violence among American Muslims is very marginal and very isolated. Our heads arent in the sand, Alejandro Beutel, the government and policy analyst for the Muslim Public Affairs Council, a national advocacy group, said at a forum his group sponsored on Monday on Capitol Hill. The threat clearly exists, but I also want to put it in perspective. The threat exists, but it is not a pandemic. Fifty-one Muslim, civil rights and interfaith groups sent a letter last week to Speaker John Boehner, Republican of Ohio, and the House minority leader, Nancy Pelosi, Democrat of California, protesting Kings hearings as modern-day McCarthyism. They said that if Congress was going to investigate violent extremism, it should investigate extremists of all kinds and not just Muslims. Singling out a group of Americans for government scrutiny based on their faith is divisive and wrong, said the letter, which was led by Muslim Advocates, a legal and policy organization in San Francisco, and was signed by non-Muslim groups including Amnesty International USA, the Interfaith Alliance and the Japanese American Citizens League. Ellison said that while he would participate, Im going to make it clear that I challenge the premise of the hearings. If you put every single Muslim in the US in jail, it wouldnt have stopped Jared Loughner, Ellison said, referring to the man accused of opening fire on an Arizona congresswoman and her constituents. It wouldnt have stopped the young man who killed his classmates at Virginia Tech. It wouldnt have stopped the bombing in Oklahoma City or the man who killed a guard at the Holocaust Museum in Washington. But King dismissed this line of criticism, saying: I totally reject that. That, to me, is political correctness at its worst. If we included these other violent events in the hearings, wed be sending the false signal that we think theres a security threat equivalency between Al Qaeda and the neo-Nazi movement, or Al Qaeda and gun groups. There is none. King added, Im not going to dilute the hearings by including other extremists. In fact, he said he planned to hold three or four more hearings this year on topics like the radicalisation of Muslims in prisons and Saudi financing for American mosques.