Washington (CNN)New York City Mayor Bill de Blasio said Thursday that Republican presidential candidate Donald Trump's claim the presidential election is rigged is reminiscent of a fascist.

"It's just a classic tool, tactic to try to undermine the Democratic process," the mayor said on CNN's "New Day."

"He's tried to turn white Americans against people of color," de Blasio told CNN's Alisyn Camerota. "We've seen this before. This is what fascists do."

Trump refusing to say at the final debate on Wednesday night that he would accept the election outcome on November 8 by casting doubt on the voting process is what you would expect to hear from a "third world dictator," said de Blasio, a Hillary Clinton supporter.