Outspoken Republican Sen. Jeff Flake of Arizona was heard on a hot mic Saturday saying the Republican Party will be "toast" if it is defined by figures like President Trump and Alabama Republican Roy Moore.

Flake, whose comments were caught on a microphone of ABC local affiliate KNXV-TV, was speaking with a friend at the time after finishing a town hall on tax reform.

"[If we] become the party of Roy Moore and Donald Trump, we are toast," Flake is overheard saying to Mesa, Arizona, Mayor John Giles.

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From the local station's cut, it isn't entirely clear how Flake began the sentence, but Flake's office told the station he used the words, "if we" before the hot mic picked up his comments. KNXV-TV's camera began to roll mid-sentence.

Sunday evening, Mr. Trump took to Twitter to call the senator "Flake(y)" and lambasted him for "saying bad things about your favorite President."

Sen. Jeff Flake(y), who is unelectable in the Great State of Arizona (quit race, anemic polls) was caught (purposely) on “mike” saying bad things about your favorite President. He’ll be a NO on tax cuts because his political career anyway is “toast.” — Donald J. Trump (@realDonaldTrump) November 19, 2017

It isn't the first time Flake has criticized Moore, Mr. Trump or the Republican Party as a whole. Flake had criticized the president for weeks before announcing he will not run for re-election in 2018, saying he "will not be complicit or silent" about the direction of the GOP. He has called the president's behavior "dangerous" for democracy.

After multiple women came forward accusing Moore of inappropriately pursuing or sexually touching them when they were teens, Flake said he would "run to the polling place to vote for the Democrat" if he was an Alabama voter.

The accusations against Moore have thrown the GOP into a political crisis, weeks ahead of the special Dec. 12 election between Moore and Democrat Doug Jones. Moore has only intensified his attacks against Senate Majority Leader Mitch McConnell, The Washington Post -- which first reported the allegations -- and his accusers themselves.

The accusations against Moore have also put the White House in a difficult situation politically, as at least 16 women have accused Mr. Trump of behaving inappropriately toward them. Mr. Trump has yet to personally address the accusations against Moore, although White House press secretary Sarah Sanders has said he believes Moore will do the "right thing" and step aside "if" the allegations are true. Sanders has refused to answer further questions about the president's own accusers.