As a caravan of migrants continues its march toward the southern U.S. border, an "Angel Mom" is calling out Congress for basically sending the message that "America's borders are open and we're welcoming anybody and everybody."

Mary Ann Mendoza -- whose police officer son was killed in 2014 by a drunk-driving illegal immigrant with a criminal record -- said illegal immigrants will continue to "invade" the U.S. as long as our immigration laws incentivize them.

"Thank goodness that we have a president who's standing up to it," Mendoza said, alluding to President Trump repeatedly stating that the caravan will not be allowed to enter the U.S. illegally and migrants must go through the proper legal processes.

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Despite Trump's strong words and the deployment of U.S. troops to the border to assist Homeland Security and the Border Patrol, the caravan is still advancing.

Fox News' William La Jeunesse reported from Oaxaca, Mexico that there are approximately 4,000 to 7,000 people in the caravan, with some dropping off and others joining.

He said the caravan is traveling about 25 miles a day, which puts it on pace to arrive in Tijuana in about 80 days.

La Jeunesse said the Trump administration is not concerned just about this caravan, but also the four other caravans forming in Central America.

"It's risk and reward. Right now, they believe the reward is greater than the risk," La Jeunesse said. "[They believe] if they get to the United States, they'll get in somehow, legally or not, and get a job."

Mendoza said it's disappointing that some immigration activists and Democratic lawmakers are trying to prevent Trump from fulfilling his campaign promise and securing the border.

"Red-blooded Americans are sick and tired of seeing this happen," Mendoza said. "We want our borders closed. We need to know who's coming into our country."

Mendoza noted that she joined other "Angel Families" at the southern border in Arizona over the weekend to take some photos and examine just how unsecured hundreds of miles of the U.S.-Mexico border is.

"It is barb wire fencing and Normandy fencing and that's all that we have." she said. "It's frightening to see what our southern border is and knowing that these amount of people are headed our way every year."

Watch more from "Fox & Friends" above.

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