A spokesman for Us first lady Melania Trump has described comments by his former wife Ivana as "distracting and self-serving noise".
Ivana Trump told ABC's Good Morning America she was "basically first Trump wife, I'm first lady".
She was married to Donald Trump in 1977 but they divorced in the 1990s over his affair with his second wife-to-be Marla Maples.
Ivana and Donald had three children - Donald Jr, Ivanka and Eric Trump.
She said she had a direct line to the White House but did not want to "cause any kind of jealousy".
Melania Trump responded with a barbed statement through her spokeswoman Stephanie Grisham.
"Mrs Trump has made the White House a home for their son Barron and The President," it read. "She loves living in Washington, DC and is honoured by her role as First Lady of the United States. She plans to use her title and role to help children, not sell books."
"There is clearly no substance to this statement from an ex. Unfortunately only attention seeking and self-serving noise."
The exchange is thought to be the only public row between a US first lady and a president's former wife.