Melania Trump's parents have received American citizenship under so-called "chain migration" rules that her husband, US President Donald Trump, has frequently derided.
The US first lady's Slovenian-born parents, Viktor and Amalija Knavs, were sworn in on Thursday in New York City, their lawyer Michael Wildes said, adding that the couple received no preferential treatment.
Asked by the New York Times if the couple had become citizens through "chain migration," Wildes answered "I suppose."
Wildes said the term was a "dirtier" way of describing "a bedrock of our immigration process when it comes to family reunification."
President Trump has frequently slammed the process under which legal US residents can sponsor the admission of family members and other people who are not close relatives.
In November, Trump tweeted that the process "must end now!"
"Some people come in, and they bring their whole family with them, who can be truly evil. NOT ACCEPTABLE!" he wrote.
Melania Trump was born Melania Knavs in what was then the communist country of Yugoslavia and later changed her surname to Knauss.
