Melania Trump's former modelling agent says she obtained a work visa before she modelled professionally in the United States in the mid-1990s.
The comments came on Thursday in response to questions about Mrs Trump's own remarks that appeared inconsistent with US immigration rules.
In an interview with The Associated Press, Paolo Zampolli offered the most detailed description yet of how the wife of the Republican presidential nominee came into the country.
Donald Trump's presidential campaign repeatedly declined to clarify her comments, discuss Mrs Trump's immigration history in detail or provide copies of any paperwork that would put the issue to rest.
Mr Trump has made illegal immigration a signature plank in his campaign platform, and his wife has often cited her path to US citizenship in defence of his hard line.
Zampolli said that while he was a partner at modelling agency Metropolitan Models, he secured a work visa for Mrs Trump, who in the mid-1990s was named Melania Knauss.
"I know she was not working a paid job before she got the H-1B," Zampolli said, referring to the type of work visa that US companies can obtain for "fashion models of distinguished merit and ability".
H-1B visas generally allow a person to work and live in the US for three years with the opportunity to renew the visas for another three years.
In interviews earlier this year with MSNBC and for a profile in Harper's Bazaar, Mrs Trump's comments appeared to be inconsistent with holding a work visa.
"I never thought to stay here without papers. I had a visa. I travelled every few months back to the country to Slovenia to stamp the visa," she said during the MSNBC interview.
US immigration law did not require such trips that Mrs Trump describes for work-visa holders at the time. People who hold visitor visas would be required to leave the country on or before the end date of their authorised stay.
US law does not allow someone to use a visitor visa to regularly live and work in the country.
Mrs Trump published a statement on Twitter on Thursday, disputing that she violated immigration laws.
"I have at all times been in full compliance with the immigration laws of this country. Period. Any allegation to the contrary is simply untrue," she wrote.
Mrs Trump has said she came to the US in 1996 on a visa, got her green card in 2001 and became a US citizen in 2006, the year after she married Donald Trump.
In her statement, Mrs Trump did not specify which visa she held during the early part of her modelling career in New York.
Zampolli said Thursday he believes Mrs Trump was confused about her visa requirements, noting that she travelled to Slovenia to visit her family multiple times.
In her statement, Mrs. Trump did not address reports in Bloomberg News, Politico and The Washington Post speculating whether nude photos taken of her in New York in 1995 were evidence that she had worked illegally in the US before securing the appropriate visa.
