Updated

Republican Sen. Jeff Flake of Arizona wrote out a $100 check to Alabama Democratic Senate candidate Doug Jones Tuesday, in an apparent response to President Trump's formal endorsement of embattled Republican candidate Roy Moore.

Flake tweeted out a picture of his donation, adding the caption, "Country before Party." The phrase was also written on the subject line of the check.

Moore responded to Flake's donation with a broadside of his own on Twitter describing Flake as a "Pro-amnesty, big gov't Republican Senator" and called for "100 grassroots conservatives to step up and reject the DC Establishment"

JEFF FLAKE: GOP IS 'TOAST' IF IT BECOMES PARTY OF TRUMP, MOORE

Moore, a former chief justice of the Alabama Supreme Court, has been accused of sexual misconduct by several women. One of the women has alleged that Moore molested her in the late-1970s, when she was 14 and he was in his early 30s.

Sen. Ben Sasse, R-Neb., who has also criticized Moore, tweeted that Flake's donation "is a bad idea," and cited Jones' position on abortion.

"It's possible to be against BOTH partial birth abortion AND child molestation," Sasse tweeted. "Happily, most Americans are."

Republican leaders in Washington, including Senate Majority Leader Mitch McConnell, called on Moore to drop out of the race after the initial allegations. However, Moore refused to step aside and Trump threw his support behind Moore with a week to go before the election.

"I think he's going to do very well. We don't want to have a liberal Democrat in Alabama, believe me," Trump said Tuesday during a lunch with Republican senators. "We want strong borders, we want stopping crime, we want to have the things that we represent and we certainly don't want to have a liberal Democrat that's controlled by Nancy Pelosi and controlled by Chuck Schumer, we don't want to have that for Alabama."

Following the White House meeting, Flake told reporters "I disagree" with the Trump's endorsement.

"I have a very different view of Roy Moore and what that does for the party," Flake said. "I do think the president is wrong here and I think it will have negative impacts on the party in the long term."

Flake has said he will not run for re-election to the Senate next year and was caught last month on a hot mic telling an Arizona mayor "if we become the party of Roy Moore and Donald Trump, we are toast."

The special election is for the seat once held by Jeff Sessions, now the U.S. attorney general. Although the polls have showed a narrowing contest between Moore and Democrat Doug Jones, Alabama is a strongly Republican state which has not elected a Democrat for U.S. Senate since Richard Shelby in 1992. Shelby switched parties two years later.

Fox News' Bree Tracey contributed to this report, along with The Associated Press.