WASHINGTON – President Trump explicitly endorsed embattled candidate Roy Moore on Monday, saying he needs a Republican in the Alabama seat to help push through key parts of his agenda such as tax cuts and the border wall.

"Democrats refusal to give even one vote for massive Tax Cuts is why we need Republican Roy Moore to win in Alabama," Trump tweeted early Monday before boarding Air Force One on a trip to Utah.

"We need his vote on stopping crime, illegal immigration, Border Wall, Military, Pro Life, V.A., Judges 2nd Amendment and more. No to Jones, a Pelosi/Schumer Puppet!" he continued. 

Citing unnamed officials, CNN and The Washington Post reported late Monday that the Republican National Committee would follow Trump's lead by supporting Moore's Senate bid.

Breitbart News first reported on the RNC's decision to jump back into Moore's corner, according to The Associated Press.

Trump, who later Monday called Moore to offer his support directly, did not mention the allegations that Moore sexually assaulted and harassed girls as young as 14 years old when he was in his 30s and an assistant district attorney. For weeks, Trump has expressed a preference for Moore and defended him against the accusations that have rocked the campaign for weeks, citing the ex-judge's repeated denials.

White House spokesman Raj Shah said Trump "had a positive call with Judge Roy Moore during which they discussed the state of the Alabama Senate race and the President endorsed Judge Moore's campaign."

Moore confirmed the Monday call, tweeting that Trump told him he "needs a fighter to help him in the US Senate" and to "go get 'em." 

The Trump-Moore union is relatively new. During the Republican primary for the Senate seat left open after Jeff Sessions became attorney general, Trump backed interim Sen. Luther Strange, R-Ala. Strange lost to Moore, whom former Trump adviser Steve Bannon endorsed. 

More: President Trump appears to back Roy Moore: 'We don't need a liberal' in Alabama Senate seat

In a separate tweet Monday, Trump described Moore's election opponent Doug Jones as a "liberal puppet" of Democratic leaders Sen. Chuck Schumer and Rep. Nancy Pelosi.

Electing Jones, Trump said, "would hurt our great Republican Agenda of low on taxes, tough on crime, strong on military and borders...& so much more."  

Moore, in his own tweet Monday, thanked Trump for his support. 

While Trump's aides have said he does not plan to campaign in person for Moore, but does have an appearance scheduled this week in northern Florida, near the Alabama border. 

While several Republicans spoke out against Moore after the allegations surfaced last month, some seem to be softening their opposition as some polls show the Republican leading in the tight race

Senate Majority Leader Mitch McConnell said Sunday that Moore will be sworn in as a senator if he wins on Dec. 12, saying he would "let the people of Alabama decide." In November, McConnell stood by Moore's accusers, saying "I believe the women," and calling on the candidate to "step aside" from the race. 

Initially, just after the sexual harassment charges against Moore arose, White House press secretary Sarah Sanders issued a statement saying Trump expected that, if the allegations are true, "Judge Moore will do the right thing and step aside." 

Trump's endorsement of Moore drew a rebuke from at least one prominent Republican: Mitt Romney, the party's 2012 presidential nominee.

Romney, who is considering a run for the U.S. Senate from Utah, mentioned one of Moore's accusers in a tweet: "Roy Moore in the US Senate would be a stain on the GOP and on the nation. Leigh Corfman and other victims are courageous heroes. No vote, no majority is worth losing our honor, our integrity."

Later on Monday, Trump visited Utah to meet with Mormon leaders and deliver a speech on public lands during his visit to Salt Lake City. Trump announced plans to shrink the size of two national monuments in Utah.

More: McConnell says Roy Moore will be sworn into Senate if he wins Alabama election

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Contributing: The Associated Press