Sen. Steve Daines endorsed Alabama's U.S. Senate candidate Roy Moore earlier this week, calling the Republican hopeful a “principled conservative” who had the experience to help reform Washington.

By Thursday, however, Republican leaders had run from Moore after the Washington Post reported that he sexually assaulted an under-age girl when he was serving as a district attorney in Alabama.

Daines, one of the few Republican senators to have endorsed Moore, has yet to withdraw his endorsement.

“These are very serious allegations and if true he should step down,” Fox News quoted Daines as saying late Thursday night.

Daines' office did not return a request Friday seeking further comment.

Earlier this week, the Post reported that Moore had assaulted 14-year old girl back in 1979. Three other women also have accused the candidate of pursuing them sexually when they were in their teens and he was in his 30s.

Moore has panned the story as being little more than a “baseless attack,” though the allegations were enough convince the National Senatorial Republican Committee to sever ties with the nominee on Friday.

Daines was quoted at length in a story published by the Alabama Political Reporter, in which he spoke highly of Moore's principled values and praised the candidate for his leadership.

Moore likewise praised Daines after the Montana senator extended his endorsement.

“Steve Daines has been a strong supporter of the Second Amendment and a vocal advocate for an immigration policy that puts the safety of the American people first,” Moore said. “I appreciate his support, and I look forward to working with him to end the Obama-era war on coal and protect the thousands of Americans who work in the coal industry.”