US President Donald Trump escalated his messy clash with former aide Omarosa Manigault Newman on Tuesday, referring to the long-time colleague, who had been the top African-American in his White House, as “that dog!” Trump tweeted a barrage of insults Tuesday morning as Manigault Newman continued promoting her White House tell-all. It paints a damning picture of Trump, including her claim that he used racial slurs on the set of his reality show The Apprentice . “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!” John Kelly is White House chief of staff. P***y grabbing, creepy compliments: 5 of Trump’s most controversial comments While Trump trades in insults on a near daily basis, deeming Manigault Newman a “dog” was a stunning move. He has also pushed back against Manigault Newman’s claim that she had heard an audio tape of him using the N-word. 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! — Donald J. Trump (@realDonaldTrump) August 14, 2018 <!--//--><![CDATA[// ><!--\n\n\n//--><!]]> 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.” Trump insisted, “I don’t have that word in my vocabulary, and never have.” He said Manigault Newman had called him “a true Champion of Civil Rights” until she was fired. Manigault Newman, the former White House liaison to black voters, writes in her new memoir that she’d heard such tapes existed. She said Sunday that she had listened to one after the book closed. Earlier, Trump accused Manigault Newman as “wacky” and “not smart” after his former co-star revealed her recording of a phone conversation with the president. Beyond their war of words, the row touched on several sensitive issues in 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, 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 Manigault Newman promotes her memoir Unhinged , which comes out officially Tuesday. The book paints a damning picture of Trump, including her claim that he used racial slurs on the set of his reality show The Apprentice . In a series of interviews on NBC, Manigault Newman also revealed two audio recordings from her time at the White House, including portions of a recording of her firing by Kelly, which she says occurred in the high-security Situation Room, and a phone call with Trump after she was fired. Manigault Newman says she has more recordings. Asked on MSNBC’s Hardball if special counsel Robert Mueller – 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.” Trump officials and a number of outside critics denounced the recordings as a serious breach of ethics and security – and White House aides worried about what else Manigault Newman may have captured in the West Wing. The tape recording appears to show Trump expressing surprise about her firing, saying “nobody even told me about it.” But Manigault Newman said he “probably instructed General Kelly to do it.” On Twitter, Trump declared Monday that she had been “fired for the last time,” a reference to her appearances on his reality TV show. He said Kelly had called her a “loser & nothing but problems,” but 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!” Trump tweeted. Responding on NBC, 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.” Trump’s battle with Omarosa underscores the racial tensions that have defined his presidency. He notably blamed “both sides” for violent clashes between white supremacists and counterprotesters in Charlottesville, Virginia, a year ago and has questioned the intelligence of other prominent black figures including California politician Maxine Waters, basketball star LeBron James and TV journalist Don Lemon. He also has targeted black NFL players for kneeling in social protest during the national anthem. Manigault Newman also alleges that Trump allies tried to buy her silence after she left the White House, offering her US$15,000 a month to accept a “senior position” on his 2020 re-election campaign along with a stringent non-disclosure agreement. The offer raises fresh question about the ways that White House aides are being offered safe landing spots after they leave. For example, Trump’s former personal aide John McEntee, who was removed from his job in April, went to the campaign. Trump tweeted Monday that Manigault Newman has a “fully signed Non-Disclosure Agreement!” It was not clear exactly what he was referring to. White House Counsellor Kellyanne Conway said Sunday on ABC that there are “confidentiality agreements” in the West Wing. And Trump’s campaign said that in the 2016 race she “signed the exact same NDA that everyone else on the campaign signed, which is still enforceable.” Meanwhile, Trump’s lawyer, Rudy Giuliani, said on Fox and Friends Monday that Manigault Newman may have broken the law by recording private conversations inside the White House. “She’s certainly violating national security regulations, which I think have the force of law,” Giuliani said. But experts in national security and clearance law said that, while she seriously violated rules – and would likely be barred from ever being granted a security clearance – she probably didn’t break any law unless the conversations she recorded were classified. In the recording with Kelly, which Manigault Newman quotes extensively in her new book, Kelly can be heard saying that he wants to talk with her about leaving the White House. “It’s come to my attention over the last few months that there’s been some pretty, in my opinion, significant integrity issues related to you,” Kelly is heard saying, before adding that if she makes it a “friendly departure” then she can “go on without any type of difficulty in the future relative to your reputation.” Manigault Newman said she viewed the conversation as a “threat” and defended her decision to covertly record it and other White House conversations, saying otherwise “no one” would believe her.