A Republican from Aurora has become the first House Republican to expressly distance himself from Donald Trump in a campaign ad.

Rep. Mike Coffman, a four-term Republican, faces a competitive challenge in Colorado's most ethnically diverse congressional seat. His Democratic opponent repeatedly compares him to Trump.

Coffman starts a new television ad talking about his party's presidential nominee. Coffman looks at the camera and says he's always asked about Trump and then says, "Honestly, I don't care for him much."

Coffman promises that if Trump is elected, "I'll stand up to him."

Coffman adds that he would also stand up to Hillary Clinton. "I certainly don't trust Hillary," Coffman says. "If Hillary wins, I'll hold her accountable every step of the way."

The 30-second ad begins airing in Denver Friday. A spokeswoman for Coffman says the campaign spent about $50,000 for cable and digital ads.

Coffman also plans to release the ad in Spanish. The district is about 20 percent Latino. Two years ago, Coffman debated his Democratic opponent in Spanish, the first Spanish congressional debate between two non-native speakers.

Colorado's 6th congressional district in Denver's eastern suburbs has been in GOP hands since its creation after the 1980 Census. But population change and changes to district boundaries have made the seat more competitive for Democrats, who consider the race their best chance this year to pick up a Congress seat in Colorado.

Coffman's opponent, former state Senate President Morgan Carroll, says Coffman is in many ways like Trump. Her spokesman pointed out that Trump has not said he won't vote for Trump, making the ad "political double-speak."

"If he wasn't going to vote for this bully, he would have already said so," Drew Godinich said in a statement.

But Coffman met recently with Libertarian vice presidential candidate William Weld, and his spokeswoman said Thursday that Coffman has not decided which presidential candidate to support.

"Like a lot of Coloradans, he's not happy with his options at the top of the ticket," said Coffman spokeswoman Cinamon Watson. She added, "But Hillary Clinton is not an option."

Coffman recently said he was "deeply offended" by Trump's criticism of the parents of a fallen soldier.