(CNN) The leading Muslim civil liberties group in America called Monday for Republican Ben Carson to drop out of the presidential race after the retired neurosurgeon said this weekend he doesn’t believe a Muslim should be president of the United States.

Nihad Awad, executive director of the Council on Islamic Foreign Relations, said the group is calling on Carson to “withdraw from the presidential race because he is unfit to lead, because his views are inconsistent with the United States Constitution.”

Awad pointed out that the Constitution clearly states that there shall be “no religious test” for candidates to seek public office.

Awad said he was “shocked” to hear Carson’s comments, which he described as anti-Muslim. He urged the public and other presidential candidates to “repudiate” Carson’s views.

Immediately following Awad’s comments, Carson’s business manager, Armstrong Williams, said on CNN that many Americans share Carson’s views about Islam.

“He has to come to the conclusion for what is best for America. In his heart of hearts he could never advocate for a Muslim to become President of the United States,” Williams said.

Carson’s comments came as he responded to another controversy about Muslims in America that emerged late last week when a questioner at a Donald Trump campaign event in New Hampshire said “we have a problem in this country … called Muslims” and insisted President Barack Obama is a Muslim. Trump did not respond to those comments during the events and has refused to disavow those views.

Carson also refused to repudiate those views and said he believed Islam was inconsistent with the U.S. Constitution.

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