CNN host Don Lemon twice branded comments made by President Donald Trump’s as racist while moderating Wednesday’s evening’s Democrat presidential primary debate in Detriot, Michigan.

In the first instance, Lemon asked Sen. Michael Bennet (D-CO) how he would as president address racial tensions “stoked by the president’s racist rhetoric.”

The CNN debate moderator then asked Obama-era HUD Secretary Julián Castro what his plan is to aid struggling cities, “after the president’s racist tweets attacking Baltimore and Congressman Elijah Cummings.” Over the weekend, President Trump slammed the longtime Maryland Democrat lawmaker’s district, calling it a “rat and rodent infested mess.”

“First of all the president is a racist and that was just one more example of it,” Castro replied, before discussing the importance of investing in education programs for children in cities plagued by poverty and crime.

During Tuesday evening’s debate, Lemon claimed President Trump “is pursuing an election strategy based in part on racial division,” and spoke of the president’s so-called “bigotry.”

President Trump took umbrage with Lemon’s Tuesday comments, writing on Twitter: “CNN’s Don Lemon, the dumbest man on television, insinuated last night while asking a debate ‘question’ that I was a racist, when in fact I am ‘the least racist person in the world.”

“Perhaps someone should explain to Don that he is supposed to be neutral, unbiased & fair or is he too dumb (stupid) to understand that,” he added.

GLAAD, the prominent LGBTQ advocacy organization, rushed to defend Lemon, who is gay, saying in a statement that the president’s “continued attacks on the intelligence of prominent black Americans are abhorrent and telling.”

This is not the first time Lemon has accused President Trump and his supporters of racism. In January, Lemon wondered why so many Trump’s supporters overlook his “racism,” claiming the issue was “personal” and “even deadly” to those like himself.

“But for people who look like me, other minorities, women who have–well, let’s just leave this to race, this president has said and done so many insensitive and bigoted and racist things that… if you support him, people like me want to understand why you ignored so much in order to support this man,” said Lemon. “You may not think you’re a racist. Maybe–I don’t know if you are. I don’t think, you know, every Trump supporter is a racist. But you certainly had to overlook racism and bigotry in order to make that decision.”

“Now, then, maybe you made that decision in the voting booth. And then, now, even after all of this, if you still, in your mind, can support this person, why the hell are you overlooking racism so much?” he asked. “It is personal and even deadly to people like me.”