A Republican member of the U.S. House of Representatives from Colorado insisted he misspoke on Wednesday after telling supporters that he wasn't sure where President Barack Obama was born but the president was "not an American."

Speaking to donors at the Elbert County Fairgrounds on May 12, Rep. Mike Coffman noted his disappointment about the state of the economy before launching into an unprompted rant about the president's citizenship.

"I don't know whether Barack Obama was born in the United States of America," the congressman said. "I don't know that. But I do know this, that in his heart, he's not an American. He's just not an American."

Elbert County Republican Chairman Scott Wills told Colorado's 9News that there was "deafening silence" before the crowd reacted with tentative applause.

Coffman supporter Brooks Imperial, who first posted audio of the speech, said he wished more Republicans would reveal they were birthers.

"I'm glad the congressman said it," Imperial remarked. "Not enough have. More should."

In a written statement on Wednesday, Coffman insisted that he had misspoke.

"I misspoke and I apologize," the statement said. "I have confidence in President Obama's citizenship and legitimacy as President of the United States."

"I don't believe the president shares my belief in American Exceptionalism. His policies reflect a philosophy that America is but one nation among many equals," the statement continued. "As a Marine, I believe America is unique and based on a core set of principles that make it superior to other nations."

A spokesman for Democratic state Rep. Joe Miklosi, who is hoping to defeat Coffman in November, said the statement proved the congressman was too extreme for Colorado voters.

"These outrageous comments once again make clear that Mike Coffman is Colorado's version of Rush Limbaugh," Miklosi spokesman Joe Hamill explained. "This kind of extremism is why Washington doesn't work."

"We need leaders who will work together for solutions, not join the far right birther fringe or attack the President of the United States as un-American," the spokesman added.

Audio of Coffman's entire speech is available here.

Watch the video below from 9News, broadcast May 16, 2012.

(h/t: Talking Points Memo)