Melania Trump has accused her husband’s first wife, Ivana Trump, of “attention-seeking and self-serving noise” after the first Mrs Trump joked that she was first lady.

On a tour to promote her new book, Raising Trump, about raising Donald Trump’s three eldest children, Ivana said she still spoke to her ex-husband about once every 14 days on a “direct number to the White House”.

She told ABC News she was reluctant to call the president too often “because Melania is there, and I don’t want to cause any kind of jealousy or something like that”.

She then added, laughing, “because I’m basically first Trump wife, OK? I’m first lady, OK?”

Ivana Trump says she has Pres. Trump's direct White House number: "I'm basically first Trump wife. I'm first lady." https://t.co/SiTlUUDX2S pic.twitter.com/0DQ5AMQ311 — Good Morning America (@GMA) October 9, 2017

That drew a curt response from Melania Trump’s spokeswoman Stephanie Grisham, who said Ivana’s comments had “no substance”.

“Mrs Trump has made the White House a home for Barron and the president. She loves living in Washington DC and is honored by her role as first lady of the United States. She plans to use her title and role to help children, not sell books,” wrote Grisham in a statement to CBS News.

“There is clearly no substance to this statement from an ex,” Grisham continued. “[T]his is unfortunately only attention-seeking and self-serving noise.”

Ivana Trump was married to Donald Trump from 1977 to 1992 and is the mother of Donald Jr, Ivanka and Eric. She writes glowingly about her marriage to the future president in the new book.

In the book, she suggests Ivanka could run for president one day and says she and Donald have a warm relationship despite the “insane” circumstances of their divorce.

But during the 2016 election, it was reported that Ivana once signed a sworn deposition alleging Donald had raped her. She sought to clarify that the accusation, which Donald has consistently denied, was not intended in a “literal or criminal sense”. Donald Trump’s lawyer amplified the issue, however, by suggesting to a reporter there was no such thing as marital rape.