WASHINGTON — Melania Trump is heading back toward the southern border of the United States. And this time, she's not wearing any particular message.

The first lady boarded her plane wearing a black shirt and white slacks for the flight. She was expected to visit centers Thursday housing migrants apprehended at the U.S.-Mexico border, including a U.S. Customs and Border Protection facility in Tucson, Arizona, according to Stephanie Grisham, the first lady's spokeswoman.

The visit comes a week after Mrs. Trump traveled to the border town of McAllen, Texas, to meet with officials there dealing with detained families. She also met with children at one of the facilities.

But that trip was overshadowed by a jacket the first lady wore to and from Texas that said on the back: "I really don't care, do u?" The first lady's spokeswoman said it was just a jacket, with no hidden message, but interest in her baffling fashion choice was a distraction from Mrs. Trump's trip. Her husband, President Donald Trump, undercut the no-message message by tweeting that his wife was saying she really doesn't care about the "fake news" media.

This time, Mrs. Trump travels amid upheaval over her husband's hard-line approach to immigration and evidence of increasing urgency over how that's playing out.

More than 2,300 children have been separated from their parents at the border in recent weeks and some were placed in government-contracted shelters hundreds of miles away from their parents.

The president last week signed an executive order to halt the separation of families at the border, at least for a few weeks, but the order did not address the reunification of families already separated.

A federal judge on Tuesday ordered that thousands of migrant children and parents be reunited within 30 days — and sooner if the youngster is under 5. The order poses logistical problems for the administration, and it was unclear how it would meet the deadline.