WASHINGTON – President Donald Trump on Tuesday referred to Omarosa Manigault Newman as "that dog" as the former senior White House adviser continued a publicity tour to promote her new book depicting Trump as a racist.

In a morning tweet, Trump praised his chief of staff, John F. Kelly, for firing Manigault Newman last year. The former reality television star was the highest-ranking black employee in the White House.

"When you give a crazed, crying lowlife a break, and give her a job at the White House, I guess it just didn't work out," Trump said. "Good work by General Kelly for quickly firing that dog!"

Trump's tweet came shortly after Manigault Newman appeared on "CBS This Morning" and released a new recording purportedly of a discussion in October 2016 among campaign aides about how to handle a tape on which Trump is said to have used the n-word.

In tweets Monday night, Trump denied ever using "such a terrible and disgusting word," and his aides have denied having strategized about how to contain the damage if such a tape surfaced. Manigault Newman has said she heard the tape of Trump using the term, which she said dates from Trump's years hosting the NBC reality show "The Apprentice."

Trump has come under fire previously for using derogatory terms to refer to women and African Americans.

At a debate during the Republican presidential primary season, he was famously asked by moderator Megyn Kelly about his tendency to call women he doesn't like "fat pigs, dogs, slobs, and disgusting animals."

More recently, Trump has repeatedly referred to Rep. Maxine Waters, D-Calif., as "low IQ" and called CNN anchor Don Lemon "the dumbest man on television."

In her book, "Unhinged," Manigault Newman claims the Trump campaign was aware of the existence of the tape from the "Apprentice" period. She describes a phone conversation about how to handle potential fallout with Lynne Patton, then an assistant to Eric Trump, a son of the president; then-Trump spokeswoman Katrina Pierson; and campaign communications director Jason Miller.

The recording played on CBS on Tuesday morning purportedly includes the voices of Patton and Pierson. CBS said it had not confirmed the authenticity of the tape.

On the tape, a person whom Manigault Newman identifies as Pierson is heard saying: "I'm trying to find out at least the context it was used in to help us figure out a way to spin it."

A person Manigault Newman says is Patton then describes having a conversation with Trump about the alleged tape: "I said, 'Well, sir, can you think of anytime this might have happened?' and he said, 'No.'"

"Well, that's not true," Manigault Newman then says on the tape.

The person said to be Pierson later says: "No, he said it. He is embarrassed."

During an appearance Monday night on Fox News, Pierson denied having had a conversation about the alleged Trump tape.

"No, Ed, that did not happen," she told host Ed Henry. "Sounds like she's writing a script for a movie."

In a statement released Monday, Patton called Manigault Newman's book "a complete work of fiction" and called the alleged Trump tape using the n-word "imaginary."

In her book, Manigault Newman says she understands that Trump used the slur "multiple times throughout the show's taping during off-camera outtakes, particularly during the first season of the Apprentice."

In tweets Monday, Trump attacked his former aide as "vicious, but not smart" and claimed that "people in the White House hated her."

His latest attack on Manigault Newman prompted immediate criticism from lawmakers and others.

"The president of the United States is calling a woman of color 'a dog.' How dare he!" Rep. Frederica S. Wilson, D-Fla., said during an interview on CNN. "He has taken this country to its knees."