President Donald Trump has repeatedly and vehemently denounced what he calls “chain migration,” in which adult American citizens can obtain residency for their relatives.

On Thursday, his Slovenian in-laws, Viktor and Amalija Knavs, became United States citizens in a private ceremony in Manhattan by taking advantage of that very program.

Asked if the Knavses had obtained citizenship through “chain migration”, their lawyer, Michael Wildes, said, “I suppose”.

He said chain migration is a “dirtier” way of characterising what he called “a bedrock of our immigration process when it comes to family reunification”.

The process is more commonly known as family-based immigration.

Melania Trump had sponsored her parents for their green cards, Mr Wildes said in describing the process by which the Knavses had become United States citizens.

“Once they had the green card, they then applied for citizenship when they were eligible,” he said.

Even as his in-laws were going through the process, Mr Trump was denouncing it.

In November, he tweeted, “CHAIN MIGRATION must end now! Some people come in, and they bring their whole family with them, who can be truly evil. NOT ACCEPTABLE!”

CHAIN MIGRATION must end now! Some people come in, and they bring their whole family with them, who can be truly evil. NOT ACCEPTABLE! pic.twitter.com/PQGeTTdRtX

— Donald J. Trump (@realDonaldTrump) November 1, 2017

Stephanie Grisham, the first lady’s communications director, said that because the Knavses are not part of the administration: “I’m not commenting on them”.

Ms Grisham directed further questions concerning the president’s views on immigration — and the immigration status of his in-laws — to the West Wing, which did not immediately respond to emails and phone calls requesting comment.

The Knavses have a relatively high profile for presidential in-laws. They frequently travel with the Trumps and split their time between New York, Palm Beach and Washington, where they stay in the White House.

Since initial reports emerged in February that the Knavses had obtained permanent residency in the United States, there has been a lack of clarity about when or how the couple received green cards.

Under immigration statutes, the Knavses would have needed to have their green cards for at least five years in order to apply for citizenship, along with fulfilling character, residency and civic knowledge requirements.

Their lawyer said that the couple had met the five-year requirement, but added, “I can’t give further comment”.

The Knavses’ lawyer said their ceremony was kept private for “security reasons. Photo: Getty

The president often rails against family-based immigration at his rallies, and has called it a pathway for terrorists to enter the country.

Typically, naturalisation ceremonies at the Jacob J Javits Federal Building at 26 Federal Plaza are large events, where groups of immigrants are sworn in as citizens en masse

The Knavses’ lawyer said their ceremony was kept private for “security reasons.”

The Knavses, both in their 70s, raised Mrs Trump in Sevnica, a Slovenian town of around 4500 people. There, Mr Knavs was a traveling car salesman and belonged to the Communist Party.

Mrs Knavs had harvested onions on her family’s farm, then worked in a textile factory, and sewed her two daughters’ clothes.

Mrs Trump was not present for the ceremony, and her parents told their lawyer she was in Bedminster, New Jersey, where the president spends time in the summer at Trump National Golf Club.

-The New York Times