Mitt Romney said Monday that electing Roy Moore to the Senate would be a "stain on the GOP" and not worth doing even for the sake of protecting a Republican majority.

"Roy Moore in the US Senate would be a stain on the GOP and on the nation," Romney said in a tweet. "Leigh Corfman and other victims are courageous heroes."

"No vote, no majority is worth losing our honor, our integrity," Romney said.

Romney's remark comes hours after President Trump officially endorsed Moore over Democrat Doug Jones. The two are neck-and-neck in the polls with just over a week until the Dec. 12 election. On Monday, Trump also encouraged Sen. Orrin Hatch, R-Utah, to seek re-election — to a seat Romney might run for if Hatch retires next year.

Moore has been accused by eight women of sexual improprieties, including Corfman, who alleges that Moore initiated a sexual encounter with her when she was 14 years old and he was 32.

Romney called in early November for Moore to leave the race in the wake of the allegations and argued he was "unfit for office."

On Sunday, Senate Majority Leader Mitch McConnell, R-Ky., when asked about Moore and said that it's up to the people to Alabama to decide who they want to send to the Senate and that he'll let them "make the call."

"We're going to let the people of Alabama decide a week from Tuesday who they want to send to the Senate, and then we'll address the matter appropriately," McConnell said, leaving open a potential Senate Ethics Committee investigation into the allegations facing Moore.