United States President Donald Trump's Slovenian in-laws on Thursday became American citizens through a family-based immigration programme that the president has publicly opposed, The New York Times reported.
Michael Wildes, the couple's immigration lawyer, confirmed they took the oath of citizenship on Thursday.
He said the pair had been living in the U.S. on green cards sponsored by Mrs Trump.
US President Donald Trump's parents-in-law have become US citizens in a private ceremony.
The couple's lawyer said they had "travailed a wonderful journey".
There are only a handful of ways immigrants can obtain green cards, and the largest share of them each year are given out based on familial connections.
Trump's plan, which Congress has resisted, would limit immigrants like his wife to sponsoring only their spouses and underage children to join them in the US, not their parents, adult children or siblings.
Canada has a MERIT-BASED system, while the USA prioritizes more FAMILY-based immigration.
Melania Trump was born in 1970 and during her childhood Slovenia, then part of Yugoslavia, was ruled by Josip Broz Tito, a communist dictator who nonetheless allowed more freedoms than other Eastern bloc leaders. To apply for US citizenship, a person must have a green card for at least five years, plus meet the character, residency, and civic knowledge requirements.
Melania Trump became a USA citizen in 2006, after entering the USA on a coveted Einstein visa for people of "extraordinary ability" in 2001 when she was working as a model.
When the Times asked Wildes if the Knavs obtained their citizenship through family-based immigration ― often pejoratively referred to as "chain migration" ― Wildes was vague.
Mr Knavs, who at 74, is two years older than Mr Trump, is thought to have worked as a vehicle dealer while Mrs Knavs, 73, worked in a textile factory. She was in Bedminster, New Jersey, at the Trump National Golf Club, where Trump is now staying. They frequently travel with the Trumps and split their time between New York, Palm Beach, Florida, and Washington, where they stay in the White House.
The couple are natives of Slovenia, where they raised Melania, but have been in the U.S. for more than a decade, says their immigration lawyer, per CNBC.