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The New Hampshire, Iowa and South Carolina Republican Party chairmen said they disagreed with Trump

"Donald Trump's bad idea and rhetoric send a shiver down my spine," said South Carolina chairman Matt Moore

Washington CNN  — 

The Republican leaders of the three most important states in the primary contest are all condemning Donald Trump’s plans to forbid Muslims from coming to the United States.

In a series of tweets and statements on Monday evening, the New Hampshire, Iowa and South Carolina Republican Party chairmen said they disagreed with Trump’s stunning call for the U.S. to ban Muslim visitors or immigrants. The chairmen – who represent the first three states to vote in the GOP presidential primary – don’t officially endorse candidates, but their thoughts behind the scenes can send messages to activists who look to them for guidance.

Matt Moore, the Republican chair in South Carolina, was the most outspoken against Trump’s plan, which was criticized by most of his Republican rivals.

“As a conservative who truly cares about religious liberty, Donald Trump’s bad idea and rhetoric send a shiver down my spine,” he tweeted. “American exceptionalism means always defending our inalienable rights, not attacking them when it’s politically convenient.”

“‘Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety.’ -Benjamin Franklin,” Moore added.

Trump and the South Carolina chairman have scuffled in the past over the deadline for the first-in-the South primary registration, as well as the front-runner’s somewhat dismissive tone of establishment GOP power brokers.

Jennifer Horn, head of the New Hampshire GOP, said Trump’s attempt to ban all Muslims from traveling to the U.S. is “un-American” and “un-Republican.”

‘“There are some issues that transcend politics. While my position is certainly political, I am an American first. There should never be a day in the United States of America when people are excluded based solely on their race or religion,” she said.

Horn has been increasingly critical of Trump in the past couple months, causing Trump’s campaign to call for her to resign because they say she has violated bylaws requiring her to stay neutral.

Iowa GOP chairman Jeff Kaufmann did not mention Trump in his reaction to the plan via Twitter, but his position was clear.

“I’m here to reiterate that our founding principles are stronger than political cynicism,” he said. “GOP believes that Obama has failed on ISIS, AND that we don’t make ourselves safer by betraying bedrock Constitutional values.”

Trump, who has previously called for surveillance against mosques and said he was open to establishing a database for all Muslims living in the U.S., made his latest controversial call in a news release. His message comes in the wake of a deadly mass shooting in San Bernardino, California, by suspected ISIS sympathizers and the day after President Barack Obama asked the country not to “turn against one another” out of fear.

Trump’s comments are likely to roil the Republican presidential race, forcing many of his opponents for the nomination to engage in a debate over whether there should be a religious test to enter America.

But his proposal was met with enthusiasm by many of his supporters, who showed their approval via social media as well as at his rally on Monday night.

“I think that we should definitely disallow any Muslims from coming in. Any of them. The reason is simple: We can’t identify what their attitude is,” said 75-year-old Charlie Marzka of Myrtle Beach, South Carolina.

Moreover, the Muslim travel ban will likely do little to dent Trump’s own popularity among Republican primary voters.

CNN’s Cassie Spodak, Elizabeth Landers and Jeremy Diamond contributed to this report.