Gov. Jared Polis on Friday denounced an attack ad launched hours earlier by fellow Democrat Andrew Romanoff that takes aim at primary rival John Hickenlooper, as Colorado’s Democratic U.S. Senate primary began to resemble a hall of mirrors of negative campaigning.

“I’m disappointed that Andrew Romanoff has chosen to throw mud and attack John Hickenlooper instead of focusing on his own vision and record,” Polis said in a statement issued Friday afternoon. He was referring to a 30-second Romanoff ad that uses footage from a decade-old Hickenlooper ad condemning negative campaign ads to attack the former two-term governor for ethics violations.

“There is much more that unites Democrats than divides us, and both John and Andrew have done a lot for Colorado,” Polis said. “I hope that Andrew reconsiders this counterproductive attack ad, so that we can put Democrats in the best position to win in November.”

Romanoff turns iconic Hickenlooper 'shower' ad on Senate primary rival

Polis, a former five-term congressman who has stayed above the fray in the heated Senate primary, added: “Winning the U.S. Senate seat in Colorado is essential to achieving a Democratic majority and moving our nation forward.”

Romanoff and Hickenlooper are facing off in the June 30 primary for the nomination to run against Republican U.S. Sen. Cory Gardner, who is seeking a second term.

Romanoff’s campaign manager rebuffed Polis’ suggestion, telling Colorado Politics that the former state House speaker intends to stay on the air with the ad, which runs statewide through the primary.

Romanoff polling shows gap with Hickenlooper closing to 12 points in Democratic US Senate primary

“Why would we hand Cory Gardner an advantage by nominating a candidate who defied a subpoena, got held in contempt and broke the law?” said Tara Trujillo. “The best way to beat Gardner — and bring a fresh, progressive voice to the Senate — is to make Andrew Romanoff the Democratic nominee.”

Hickenlooper supporters called on Romanoff to pull down the ad soon after it launched Friday morning, hinting that the intraparty attack could boost Gardner’s re-election chances.

“[T]his is not what we do as Democrats,” said Arapahoe County Commissioner Bill Holen, who switched his endorsement from Romanoff to Hickenlooper on Friday. “We need to focus on winning back the Senate. Andrew should take this ad down and focus on the issues.”

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The ad features excerpts from an iconic 2010 ad Hickenlooper aired when he first ran for governor. In that ad, Hickenlooper takes repeated showers with his clothes on while condemning negative campaigning.

“Scrub harder, Hick,” the Romanoff ad’s narrator says as headlines float across the screen detailing the findings of a state commission that Hickenlooper violated a state ethics law, as well as the candidate’s recent apology for a 6-year-old gaffe comparing politicians to slaves.

“Whoa,” the narrator says. “We can’t take this kind of risk if we’re going to beat Cory Gardner.”

Democrats swing back at GOP ad attacking Hickenlooper for ethics violations

Meanwhile, national Republicans continued airing a blistering attack ad that enumerates Hickenlooper’s ethical violations and a contempt charge earned when Hickenlooper spurned a subpoena to appear before the ethics commission at an online hearing.

The Republican National Committee’s Colorado spokesman sounded like he was breaking out the popcorn as the Democrats hurled criticism and attacks at each other Friday.

“Hot Mess Hickenlooper’s support is evaporating because Coloradans are learning more about his illegal and unethical conduct,” said Kyle Kohli in an emailed statement. “The collective meltdown from Polis and other establishment Democrats exposes how worried Chuck Schumer is about Hickenlooper’s candidacy.”