President-elect Donald Trump has nominated a man for secretary of Housing and Urban Development who thinks Islam isn’t a religion and has argued that there’s a covert Muslim plot to destroy the U.S. from within. It’s concerning that Ben Carson is set to fill a seat in Trump’s Cabinet, a Muslim civil liberties group said Monday.

“Based on his past Islamophobic statements and policy positions, all Americans should be very concerned on how Dr. Carson would treat Muslim HUD employees or Muslims seeking agency services,” Robert McCaw, government affairs director at the Council on American-Islamic Relations, said in a statement.

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Carson, a retired neurosurgeon and former Republican presidential candidate who has never held public office, has made many blatantly incorrect ― not to mention deeply disparaging ― remarks about Islam.

Carson doesn’t think Islam is a religion.

During a January campaign speech in Iowa, Carson suggested the rise of the self-described Islamic State was inevitable because Islam was inherently violent.

When a Mother Jones reporter asked him what he wanted people to glean from his speech, Carson said people “don’t understand the whole apocalyptic vision that they [Muslims] have. When you understand that, you understand what drives an organization like ISIS.”

It’s common for anti-Muslim groups to depict Islam ― a faith practiced by 1.7 billion people ― as a political ideology rather than a religion.

“It’s really not, once you read it, you won’t call it a religion, you’ll call it a life organization system,” Carson said when pressed further on whether he was talking about all of Islam or just ISIS.

He believes there’s such a thing as “civilizational jihad.”

Carson told Breitbart News’ Steve Bannon in February that he was concerned about a “civilizational jihad” against the U.S. wherein “jihadists” who “disguise themselves as moderate Muslims” would “infiltrate, multiply and take positions of power” in order to “replace our Judeo-Christian values with Islam.”

The idea of “civilizational jihad” is a popular and thoroughly debunked conspiracy theory. It holds that Muslims have somehow conspired to eliminate and destroy Western civilization from within. It has been promoted extensively by Frank Gaffney, who heads up the the Center for Security Policy, which the Southern Poverty Law Center considers a hate group.

Listen to the conversation between Carson and Bannon, who has since been named Trump’s chief strategist:

Carson once said Muslims can only embrace American democracy if “they’re schizophrenic.”

Bannon also asked Carson whether he thinks Muslims who are “Sharia adherent” can participate in a Democratic society governed by the rule of law. (Sharia, a favorite bogeyman of anti-Muslim circles, is the deeply misunderstood legal or philosophical code of Islam.)

“Only if they’re schizophrenic,” Carson replied. “I don’t see how they can do it otherwise, because they have two different philosophies boring at you [that contradict each other]. That would be very difficult.”

Carson said a Muslim person shouldn’t be president, and that Islam isn’t “consistent” with the Constitution.

“I would not advocate that we put a Muslim in charge of this nation,” Carson said during a September 2015 appearance on NBC’s “Meet the Press.” “I absolutely would not agree with that.”

When host Chuck Todd asked him whether a presidential nominee’s faith should be important to voters, Carson replied by saying, “I guess it depends on what that faith is. If it’s inconsistent with the values and principles of America, then of course it should matter. But if it fits within the realm of America and consistent with the Constitution, no problem.”

Then asked if he considers Islam to be consistent with the Constitution, Carson said: “No, I don’t ― I do not.”

When a host on Newsmax cited a poll showing 51 percent of Americans wouldn’t vote for a Muslim for president, Carson laughed and said he was “surprised” that number wasn’t higher.

And he once claimed to have seen nonexistent footage of American Muslims celebrating on 9/11.

WATCH: @RealBenCarson tells ABC he saw news footage of Muslims in New Jersey cheering as towers fell on 9/11:https://t.co/DJCSJdZxXS — ABC News Politics (@ABCPolitics) November 23, 2015

After Trump claimed he had seen a video of Muslims in New Jersey cheering after the Sept. 11 terror attacks, Carson said he “saw the film” as well.

But that footage doesn’t exist, and never has. Anti-Muslim hate sites were largely responsible for spreading the lie that the attacks had caused thousands of Muslims near New York City to celebrate. (Muslims in New Jersey were actually grieving after 9/11.) Carson later apologized for the remark. Trump did not.

Trump is surrounding himself with Islamophobes.

Carson is among several people with deeply questionable views regarding Islam who Trump has selected to advise him in the White House.

There’s Bannon, the president-elect’s chief strategist, who thinks anti-Muslim hate group leaders are experts on Islam. He is also the executive chairman of Breitbart News, a site that regularly publishes virulently anti-Muslim articles written by people the SPLC categorizes as hate group leaders. “STOPPING ISLAMIC IMMIGRATION IS A MATTER OF SURVIVAL,” screams one Breitbart headline.

Michael Flynn, a retired U.S. lieutenant general who is a board member and adviser for the anti-Muslim group Act for America, was tapped as a national security adviser. Flynn once likened Islam to a cancer, and has said he doesn’t “see Islam as a religion” but “as a political ideology.”

Other nominees ― including Sen. Jeff Sessions (R-Ala.) for attorney general and Rep. Mike Pompeo (R-Kan.) for CIA director ― have a history of anti-Muslim political speech.

Clare Lopez, an anti-Muslim conspiracy theorist who works at the Center for Security Policy, is reportedly being considered as a deputy national security adviser.

On Monday, American Muslim leaders wrote Trump an open letter. They’re calling on him to “reconsider and reject” many of the people he has named to his administration who have “a well documented history of outright bigotry directed at Muslims or advocating that Muslims should not have the same rights as their fellow Americans.” Over 300 people signed the letter.

Neither the Trump team nor a Carson spokesman responded to a request for comment on this story.

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