White House trade adviser Peter Navarro praised President Donald Trump s threat to slap sweeping tariffs on Mexican imports, claiming that the countrys biggest export to the U.S. is illegal aliens.

There should be no surprise that President Donald J. Trump has taken a firm stand on border security, Navarro told CNBC on Friday. This particular measure, if you look at from an investors point of view and a corporate point of view, what we have in Mexico is the export one of their high exports of illegal aliens, and its a criminal enterprise.

Navarro went on to claim that we see illegal aliens flood into our cities and deprive people in those cities of good-paying jobs.

A November 2018 Pew Research report found that many of the roughly 11.3 million undocumented immigrants living in the U.S. down from 2007s peak of 12.2 million work in the service or construction industries. A more detailed breakdown of the data shows that in 2016, some of the occupations with the highest percentages of unauthorized immigrants were roofers, drywall installers, agricultural workers, painters and maids.

Farms, in particular, would face major employee shortages without undocumented workers, as they account for more than half of the hired hands, according to a U.S. Department of Agriculture estimate.

However, like Navarro, Trump has insisted that illegal immigration constitutes an extraordinary threat to the national security and economy of the United States.

On Thursday, Trump announced on Twitter that as of June 10, his administration would impose a 5% tariff on all goods entering the U.S. from Mexico until such time as illegal migrants coming through Mexico, and into our Country, STOP.

In a statement released by the White House, Trump said the tariff would be hiked to 10% in July, 15% in August, 20% in September and 25% in October.

Urging investors to look at this calmly, Navarro commended the plan as a smart one. This is actually a brilliant move by the president to get Mexicos attention to get them to help us, because so far theyve just been standing by, and they really have the power to help, he said.

Whats happening now is Mexico, by being a bystander in this criminal enterprise, is imposing enormous costs on the United States, on our welfare system, on our criminal justice system, Navarro added.

A National Academy of Sciences study released in 2016 and cited by a 2019 New York Times fact check noted that both legal and illegal immigration benefit the U.S. economy. The report estimated that between 2011 and 2013, state and local governments faced about $1,600 per year in expenses generated by the average immigrant, but their children and grandchildren more than made up for the costs by paying taxes.