Cindy McCain, the widow of GOP Sen. John McCain, on Friday slammed the idea of a wall to curtail human trafficking at the southern border, which President Donald Trump has repeatedly cited as a problem in an attempt to build support for his long-promised barrier.

"The people that are coming over the border, for the most part, are not trafficked individuals," McCain told NBC News' Cynthia McFadden in an interview. "It's people within our own walls, in our own borders, so a wall is not going to fix this, but education will and awareness will and strengthening our laws will."

She added, "The misnomer in this is that somehow this occurs outside the country, that somehow its another country — not us, ever us. Well, it is very much us. The trafficking I'm talking about with you is domestic trafficking, these are domestic individuals being trafficked."

McCain has been an outspoken advocate for stopping human trafficking. She currently serves on the Arizona governor's council on human trafficking and has worked with officials in her home state to raise awareness and fix laws around the issue.

She also heads the human trafficking initiative at the McCain Institute and was in New York City to participate in the 10th annual Women in the World program at Lincoln Center.

This past February, at an event on human trafficking, Trump claimed that human traffickers were "going through a border where there's nobody for miles and miles, and there’s no wall to protect," adding that "they come into our country and they sell people." The president also repeated the claim in State of the Union address this year.

In her NBC News interview on Friday, McCain also lamented the lack of civility in Washington and said that her husband, who died last August, would have wanted lawmakers to debate one another on the issues but work together on a bipartisan basis.

"I am quite certain he knows what's going on," she said. "I know he'd be so upset over this because of the tenor, the lack of inaction on many members' parts, specifically on members of Congress. He would've been right in the mix saying we're going to work together, please let’s not fight. That's who he was."

She added: "Oh, he loved a good fight. Heck, yeah. But it was never personal with him. He and Ted Kennedy used to fight like cats and dogs on the floor. But they were the best of friends. I wish we could go back to that."

McCain did not directly address hostile comments Trump has made about her husband.