A progressive Super PAC is launching a new digital ad dinging Republican Sen. Dean Heller for staying silent over Alabama Senate candidate Roy Moore’s alleged sexual misconduct with an underage girl.

A digital ad produced by American Bridge 21st Century is launching Saturday on social media sites, including Facebook, Twitter and YouTube, targeting what it calls Heller’s “cowardly silence” toward what a spokesman for the group called “persuadable Nevada voters.”

The 30-second spot largely recaps media coverage of The Washington Post’s report that Moore — a conservative firebrand and former Alabama Chief Justice — made inappropriate sexual advances and pursued and attempted to date women between the ages of 16 and 18 while in his early 30s. Moore has strongly denied the allegations and called them “fake news.”

The ad concludes by asking what Heller “has to say about his party’s nominee,” and then showing a short clip of Heller silent at an unrelated, earlier press conference while urging viewers to contact his Washington, D.C. office.

At least 19 Senate Republicans, including Majority Leader Mitch McConnell, have suggested Moore should step down from the Senate race if the allegations are found to be true. Arizona Republican Sen. John McCain went a step further, calling the allegations “deeply disturbing and disqualifying” and calling on Moore to immediately step aside.

Heller’s Senate and campaign offices did not respond to multiple requests for comment from The Nevada Independent on the allegations surrounding Moore.

The National Republican Senatorial Committee officially dropped Moore from a joint fundraising agreement with the PAC, though the Republican National Committee and Alabama Republican Party remained part of the agreement.

The Super PAC plans to replicate the ad in other high-profile Senate races. A spokesman for the PAC declined to say how much money was being spent on the advertising campaign.

Heller’s only comments on Moore came in an interview with the Associated Press in September, telling the news organization he was unaware the former Alabama chief justice had defeated incumbent Sen. Luther Strange in the state’s Republican primary.

"Who won? I wasn't paying attention," Heller said at the time. "I'm just worried about taxes."

A spokesman for Democratic Sen. Catherine Cortez Masto also declined to comment Friday on the allegations against Moore.