President Trump warned Thursday he will use the U.S. military to close the southern border with Mexico if officials there don’t stop a growing migrant caravan that's swelled in size to about 4,000 people.

The president’s latest threat against the caravan that originated in Honduras – and which is heading to the U.S. in a bid to escape Honduras’ poverty and violence – comes as Secretary of State Mike Pompeo is heading to Central America to talk with leaders about the issue.

On "Fox & Friends" Thursday, "Angel Mom" Mary Ann Mendoza said she "absolutely, 100-percent" supports Trump's idea of closing the border.

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"This is what's needed to happen for a long time," Mendoza said. "We have the right to protect the citizens of this country. ... We have got to get strong and get serious, and let these people know this isn't a joke."

Mendoza -- whose police officer son was killed in 2014 by a drunk-driving illegal immigrant with a criminal record -- said people will continue finding ways to cross the "porous" U.S.-Mexico border until Trump's long-promised wall is in place.

"It's sad that that is what our southern border is and that's what people find acceptable," Mendoza said, noting that more than 4,300 Americans are killed every year by illegal immigrants and thousands more are affected by illegal immigrant crime.

"You have got to start standing up for your fellow Americans. It's ridiculous the amount of support and sanctuary that's provided for illegal aliens present in our country breaking our law. I'm stunned [by] what this country has become."

Watch more from "Fox & Friends" above, including Mendoza's message to Nancy Pelosi after the California Democrat's controversial "manhood" comment.

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