A lawyer representing Melania Trump’s parents has said they are living legally in the US.

The lawyer says Slovenian nationals Viktor and Amalija Knavs “are both lawfully admitted to the United States as permanent residents”.

Michael Wildes declined further comment, and did not discuss when the couple would be eligible for citizenship or how their green cards were obtained.

Immigration experts said the couple might have relied on a family reunification process criticised by Trump as “chain migration”. He has pushed to limit immigrants’ ability to sponsor relatives to join them in the US, and has endorsed legislation that would prevent immigrants from sponsoring their parents.

David Leopold, an immigration lawyer, told the Washington Post said it was likely Melania had sponsored her parents so they could obtain green cards.

“That would be the logical way to do it, the preferred way to do it, and possibly the only way to do it under the facts that I know,” Leopold said.

Trump’s new proposal would only allow immigrants to sponsor spouses and minor children.

A spokeswoman for the first lady says the Knavs “are not part of this administration and deserve their privacy”.

Melania Trump has been a US citizen since 2006.