US president Donald Trump has called his former adviser Omarosa Manigault Newman a “dog”.

Ms Manigault Newman has released several audio recordings from her time as an assistant to Mr Trump at the White House, including one with the president in which he said nobody told him she had been fired.

The president’s former TV co-star on The Apprentice also said she has heard audio tape of Mr Trump using the N-word.

Donald Trump
Ms Manigault Newman is releasing a tell-all book about Mr Trump (AP)

On Tuesday, Mr Trump tweeted: “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. Good work by General Kelly for quickly firing that dog!”

That is a reference to Mr Trump’s White House chief of staff, retired general John Kelly, who sacked Ms Manigault Newman in December 2017 in a conversation she viewed as a “threat”.

Mr Trump has also retaliated after Ms Manigault Newman claimed she had heard an audio tape of him using racial slurs while they worked on The Apprentice.

He tweeted that he had received a call from the producer of The Apprentice, assuring him “there are NO TAPES of the Apprentice where I used such a terrible and disgusting word as attributed by Wacky and Deranged Omarosa”.

The president insisted: “I don’t have that word in my vocabulary, and never have.”

He said Ms Manigault Newman had called him “a true Champion of Civil Rights” – until she was sacked.

Ms Manigault Newman, the former White House liaison to black voters, writes in her new memoir that she had heard such tapes existed. She said on Sunday that she had listened to one.

Earlier, Mr Trump accused Ms Manigault Newman of being “wacky” and “not smart” after his former co-star revealed her recording of a phone conversation with the president.

Omarosa Manigault Newman
Ms Manigault Newman came under stinging criticism after releasing audio recordings (AP)

Beyond their war of words, the row touched on several sensitive issues in Mr Trump’s White House, including a lack of racial diversity among senior officials, security in the executive mansion, a culture that some there feel borders on paranoia and the extraordinary measures used to keep ex-employees quiet.

In an unusual admission, Mr Trump acknowledged that the public sparring was perhaps beneath a person in his position, tweeting that he knew it was “not presidential” to take on “a lowlife like Omarosa”.

But he added: “This is a modern day form of communication and I know the Fake News Media will be working overtime to make even Wacky Omarosa look legitimate as possible. Sorry!”

The dispute has been building for days as Ms Manigault Newman promotes her memoir Unhinged, which was officially released on Tuesday.

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Ms Manigault Newman alongside presidential adviser Kellyanne Conway (AP)

In a series of interviews on NBC, Ms Manigault Newman also revealed two audio recordings from her time at the White House, including portions of a recording of her firing by Mr Kelly, which she said occurred in the high-security Situation Room. She also released a tape of a phone call with Mr Trump after she was fired.

Ms Manigault Newman says she has more recordings. Asked on MSNBC’s Hardball if special counsel Robert Mueller – who is investigating possible coordination between the Trump campaign and Russia – would be interested in any of them, she said: “If his office calls again, anything they want, I’ll share.”

Mr Trump’s officials and a number of outside critics have denounced the recordings as a serious breach of ethics and security – and White House aides worried about what else Ms Manigault Newman may have captured in the West Wing.

The tape recording appears to show Mr Trump expressing surprise about her sacking, saying: “Nobody even told me about it.” Ms Manigault Newman said he “probably instructed General Kelly to do it”.

Omarosa Manigault Newman
Ms Manigault Newman was sacked as director of communications for the White House office of public liaison (AP)

On Twitter, Mr Trump declared that she had been “fired for the last time”, a reference to her appearances on his reality TV show. He said Mr Kelly had called her a “loser & nothing but problems”, although he himself had tried to save her job – because he liked her public comments about him.

“I told him to try working it out, if possible, because she only said GREAT things about me – until she got fired!” Mr Trump tweeted.

Responding on NBC, Ms Manigault Newman said: “I think it’s sad that with all the things that’s going on in the country that he would take time out to insult me and to insult my intelligence.”

She added: “This is his pattern with African-Americans.”

First lady Melania Trump, meanwhile, is disappointed that Ms Manigault Newman “is lashing out and retaliating in such a self-serving way, especially after all the opportunities given to her by the president”, according to White House spokeswoman Stephanie Grisham.