The visit came a week after Mrs Trump wore a jacket with a message on the back to and from the border town of McAllen, Texas that overshadowed her visit with officials and some migrant children. But the first lady's husband undercut the no-message message by tweeting that she was saying she really doesn't care about the "fake news" media.
A federal judge ruled that U.S. immigration agents could no longer separate immigrant parents and children caught crossing the border from Mexico illegally and must work to reunite those families that had been split up in custody.
A protest against the separation of children from immigrant parents is planned for Saturday in downtown Muskegon.
For her second trip to the border to visit the border since the family separation crisis, Melania Trump has gone back to basics.
The agency would continue to refer single adults for prosecution for illegally crossing the border, said the CBP chief, adding that border agents would also separate children from adults if the child was in danger or if the adult had a criminal record.
Her first stop was a Customs and Border Protection processing facility in Tucson, Arizona, where immigrants apprehended after illegally crossing into the country are held.
AL governor, retail association praise SCOTUS online sales tax ruling
The ruling is "a big, big victory" for them and was a "good decision", President Donald Trump told governors at the White House. Retail trade groups praised the ruling, saying it levels the playing field for local and online businesses.
The first lady's visit to Phoenix stemmed from the crisis surrounding President Trump's "zero-tolerance" prosecution policy of migrant families who cross the U.S. -Mexico border. "She told her staff she wanted to go, and we made that happen", Grisham said.
"If this is an issue of importance to the first lady, the field is vast for engagement and follow-up and her voice", she said.
Southwest Key is a nonprofit that runs 26 immigrant shelter facilities for children across Texas, Arizona and California.
"Thank you for all your hard work that you do, and I know how risky and difficult your daily jobs are", Trump said at a briefing with border patrol and immigration enforcement officials and local ranchers.
Anticipating a trip to Phoenix, protesters also gathered outside the Southwest Key facility in the city's west side.
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 five. It's not clear yet how the administration will meet the deadline.