Dozens of evangelical leaders are condemning what they call “radicalized Christian nationalism” for contributing to the political extremism exposed in the Jan. 6 attack by Trump supporters on the U.S. Capitol.

More than 100 clergy and other prominent evangelicals signed an open letter expressing their concern about growing “radicalization” among white evangelicals, branding it an “on-going sin” committed by many believers.

“The letter notes that some members of the mob that stormed the Capitol carried Christian symbols and signs that read ‘Jesus Saves,’ and that one of the rioters stood on the Senate rostrum and led a Christian prayer,” says NPR, which was first to report the story.

The letter calls on other Christian leaders to take a public stand against racism, Christian nationalism, conspiracy theories and political extremism,” NPR says.

White evangelicals played a central role in Trump’s “base” during his term in office, with a majority supporting him in both his victorious 2016 presidential campaign and last November, when he lost.

“A recent survey by the American Enterprise Institute found that 3 in 5 white evangelicals believe — falsely — that President Biden was not legitimately elected,” NPR says.

In their letter, the religious leaders state that they “recognize that evangelicalism, and white evangelicalism in particular, has been susceptible to the heresy of Christian nationalism because of a long history of faith leaders accommodating white supremacy,” adding that they “choose to speak out now because we do not want to be quiet accomplices in this on-going sin.”

“Christian nationalism” is the belief that the U.S. is fundamentally Christian and run by and for white conservative Americans.

The signers of the letter blame other church leaders for allowing Christian nationalism to flourish within their ranks and for “giving participants the false impression that their actions were ‘blessed by God,’” reported The Guardian, which pointed to the findings of a recent poll by the conservative American Enterprise Institute.

That survey, conducted earlier this month, found that 60% of white evangelicals continue to believe Trump’s “big lie” that last November’s election was stolen from him and that he should have been returned to the White House, The Guardian says.