In a phone call after the ceremony, Wildes described the process by which the US First Lady's parents had become US citizens. Her husband, Donald Trump, has proposed ending most family-based immigration, which he refers to as "chain migration".
Mr Wildes called family-based migration "a bedrock of our immigration process", and when asked if the pair had gained citizenship through the system reportedly replied, "I suppose".
"He said, 'Hey look, there's people, nice people, they're relaxing, some are jogging, '" Donald Trump said during a rally last week in Wilkes-Barre, Pennsylvania, lamenting the lives lost and injured. Wildes told the newspaper that the Knavs fulfilled the five-year requirement, but declined to give further comment.
Viktor, 74, and Amalija, 73, had been living as permanent residents in the US.
The president proposed replacing most family-based immigration with a skills-based system after an attempted bombing by a Bangladeshi immigrant in NY last December. Trump has advocated a "merit-based" system, but has not proposed any method of admitting immigrants to the U.S. to replace those categories. While the president never names Saipov, who obtained his green card through the equally maligned diversity lottery, which grants visas to people from countries that have had fewer immigrants, he has been known to detail the attack.
Trump has taken a hardline on immigration policy, criticizing so-called main migration that allows naturalized U.S. citizens to sponsor close relatives for permanent residency.
Experts estimate those measures, so far resisted by Congress, would cut legal immigration into the United States almost in half.
The Knavses' citizenship ceremony was kept hush-hush around the Jacob K Javits Federal Building.
She settled in NY in 1996, met the future president two years later and became his third wife in 2005.
Wildes wouldn't say how long the Knavses have lived in the US.
Trump hasn't commented or tweeted about his in-laws' newfound citizenship.
Melania grew up in a two bedroom apartment in Sevnica, a small city formerly under communist control.
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.