Former US First Lady Melania Trump has "with deep sadness" announced the death of her mother, Amalija Knavs, at the age of 78.

"Amalija Knavs was a strong woman who always carried herself with grace, warmth, and dignity," she said.

The cause of death was not disclosed in the brief statement on X, formerly Twitter.

Donald Trump mentioned this month at an event in Florida that his Slovenia-born mother-in-law was "very ill".

Mrs Trump said in her statement on Tuesday night: "She was entirely devoted to her husband, daughters, grandson, and son-in-law.

"We will miss her beyond measure and continue to honor and love her legacy."

It was reported that Mrs Trump had been looking after her ailing mother when the former first lady's absence was noted from last month's Trump family Christmas photo at Mar-a-Lago in Palm Beach.

Mrs Knavs and her husband, Viktor, became US citizens in 2018 after living in the US on green cards sponsored by Mrs Trump.

She had worked at a textile factory in the Slovenian town of Sevnica, while her husband Viktor was a car salesman.

Mrs Trump attended high school in the Slovenian capital, Ljubljana.

She met Donald Trump in 1998 while working as a model, and had a son, Barron, with him in 2006 - the same year she became a US citizen.