The White House is refusing to discuss the immigration status of first lady Melania Trump's parents.

The Washington Post reported that the first lady's spokeswoman initially declined to comment on the matter.

"I don't comment on her parents, as they live private lives and are not part of the administration," said Stephanie Grisham, spokeswoman for the first lady, according to the Post.

A White House official also declined to comment when asked if the first lady's parents came to the U.S. via so-called "chain migration," which the president has frequently criticized.

"I'm not going to get into specific cases," the official told reporters Wednesday.

The Post listed a number of possibilities for the status of Melania's parents - Viktor and Amalija Knavs - including the possibility that they are in the U.S. on IR-5 visas, which means they are legal permanent residents, or the possibility they could be here on tourism visas and asked for extensions.

According to the Post, when it showed its list of possible options to Trump's spokeswoman, she said: "None of those options apply."

"As we noted, we gave Grisham, the first lady's spokeswoman, ample opportunity to explain the immigration status of the Knavses," the Post wrote in its fact-checker piece.

"It's a mystery why the White House refuses to answer such a simple question, given the president's high-profile demand to limit immigration."

Viktor Knavs is a former member of the Yugoslav Communist Party. Amilija Knavs worked at a textile factory. According to the Post, the couple is now retired.

The Knavses have been living in the U.S. for at least a year, according to reports.

President Trump has made immigration a key part of his agenda.

Last year the president kicked the immigration fight to Congress when his administration announced it was ending the Deferred Action for Childhood Arrivals (DACA) program, which allows certain immigrants brought into the country illegally as children to work and go to school without fear of deportation.

The immigration fight has taken center stage this week in the Senate, but Majority Leader Mitch McConnell (R-Ky.) has indicated the debate will conclude by the end of this week, which means immigration reform could once again fall short.