President Trump lashed out at John Bolton on Sunday, calling him a "real dope" and "one of the dumbest people in government" after the former national security adviser urged GOP Party leaders to accept the 2020 election results and encourage their supporters to acknowledge defeat.

“John Bolton was one of the dumbest people in government that I’ve had the “pleasure” to work with,” Trump tweeted. “A sullen, dull and quiet guy, he added nothing to National Security except, “Gee, let’s go to war.” Also, illegally released much Classified Information. A real dope!”

Trump was responding to Bolton’s appearance on ABC’s This Week with George Stephanopoulos earlier Sunday, during which he dismissed Trump's "baseless" claims of voter fraud, and urged Republican leaders to explain to supporters that "Trump has lost the election."

TRUMP ACKNOWLEDGES BIDEN 'WON' ELECTION, CLARIFIES HE'S NOT CONCEDING 

“I think it’s very important for leaders in the Republican party to explain to our voters, who are not as stupid as the Democrats think, that, in fact, Trump has lost the election and that his claims of election fraud are baseless,” Bolton said. "The fact is that we’ve seen litigation in all the key battleground states, and it has failed consistently. Right now the Trump campaign is doing the legal equivalent of pinching pennies.”

He reiterated, "It's critical for other Republican leaders to stand up and explain what actually happened: Donald Trump lost what, by any evidence we have so far, was a free and fair election."

Trump has a long history of Twitter attacks against Bolton, who left his White House post in September 2019 and has since become an outspoken critic of the president and his administration.

The latest public spat came just hours after Trump signaled for the first time that Joe Biden "won" the 2020 election that he believes was "rigged" against him, but maintained that he has no plans to concede the race.