President Trump conceded that a wall is a "medieval" solution to the border, but said it still works. The president made the remarks in his first public appearance since Tuesday night's prime-time address, during a bill signing at the White House.

Some people, the president said, call a border wall a "medieval solution" to the situation at the southern border, but they used walls at that time because they worked.

"They say it's a medieval solution, a wall. It's true because it worked then and it works even better now," the president said.

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Mr. Trump also claimed federal workers going without pay will be "happy," and suggested many of the are posting on social media to support his cause.

"They're all going to get their money and I think they're going to be happy ... you take a look at social media, so many of those people are saying it's very hard for me, it's very hard for my family, but Mr. President you're doing the right thing," Mr. Trump said.

The bill the president signed is an anti-human trafficking bill that will renew programs that make federal resources available to human trafficking survivors and establish new prevention, prosecution and collaboration initiatives to help bring perpetrators to justice. It's a bipartisan measure that passed both the House and Senate unanimously.

It's unclear what comes next in the president's border wall funding fight, although he will be meeting with Senate Republicans on Capitol Hill Wednesday, and congressional leaders will come to the White House Wednesday afternoon. It's also not yet known how much the president's address changed public opinion.

On Tuesday night, the president looked to make his case to the American public that illegal immigrants are bringing drugs and crime into the U.S., demanding immediate action to erect barriers at the border and further increase technology to prevent illegal crossings. Mr. Trump will be traveling to the southern border Thursday to further make his case.

"Some have suggested a barrier is immoral," the president said Tuesday night. "Then why do wealthy politicians build walls, fences, and gates around their homes? They don't build walls because they hate the people on the outside, but because they love the people on the inside. The only thing that is immoral is the politicians to do nothing and continue to allow more innocent people to be so horribly victimized."

Some Republicans are already calling for the federal government to reopen, and Democratic Sen. Chris Coons, D-Delaware, said he thinks there will be a tipping point "soon" in which more Republicans will break with the president.

Steven Portnoy contributed to this report.