In 2015 alone, over 30,000 illegal immigrants from “countries of terrorist concern” entered the United States through the southwestern border with Mexico, Department of Defense Southern Command (Southcom) spokeswoman Army Col. Lisa A. Garcia told the Washington Free Beacon on Monday.

“Networks that specialize in smuggling individuals from regions of terrorist concern, mainly from the Afghanistan-Pakistan region, the Middle East, and East Africa, are indeed a concern for Southcom and other interagency security partners who support our country’s national security,” Garcia said. “There are major hubs that serve as entry points into the region for migrants from those areas of concern attempting to enter the U.S. along our border with Mexico.”

Garcia reported that in 2015 alone, “we saw a total of 331,000 migrants enter the southwestern border between the U.S. and Mexico, of that we estimate more than 30,000 of these were from countries of terrorist concern.”

She explained a new Southcom report found that Sunni extremists are infiltrating the United States with the help of alien smugglers in South America and are crossing the border with ease.

While many American security officials and private security experts have dismissed the idea that terrorists exploit alien smuggling networks as a myth, the report revealed terrifying evidence that Islamist infiltration may already have occurred.

“This makes the case for Trump’s wall,” a security official noted in the report. “These guys are doing whatever they want to get in the country.”

The Washington Free Beacon’s Bill Gertz also quoted Southcom commander Adm. Kurt Tidd, who warned that a lack of information is hampering security efforts against alien smuggling. “Our ability to track people moving through transportation systems is an area that we must continue to devote efforts on, and the ease with which human traffickers are able to use our transportation systems to move people through the networks relatively undetected should give us all concern.”

The threat does not come from new relationships between Sunni extremists and alien smugglers, but from increased use of already existing networks, explained Joel Vargas, head of Continent Security Services and a consultant to law enforcement agencies. In an email statement, he warned that “existing smuggling networks from Central America are increasing their access.”

“Our Sunni illegal migration coming from [Latin America] is very small,” Vargas admitted. But “on the other hand, they can use the networks set up by the Shia.” He reported that law enforcement agencies have intercepted immigrants coming from Asia but have not been able to determine if they are extremists.

Next Page: Hezbollah in Latin America?

Vargas authored a report warning that the Iran-backed Shiite terror group Hezbollah has ties to Latin America through Lebanese expatriates. The terror group recently increased its supply of arms and training to various groups in the region. “Hezbollah’s current goals appear to be focused on accruing resources rather than conducting offensive operations, however the group’s growing capabilities are still a clear threat to regional U.S. interests,” according to the report.

“Iran’s involvement in Latin America is also increasing, and Hezbollah will likely be able to use these budding political and economic ties as cover for its operations.”

Vargas pointed to Guatemala as a weak link for security services, noting that a sophisticated smuggling operation in that country has been capable of moving immigrants into the United States from Africa and other countries for the past six years.

This bolsters a June report from the Washington Times that an immigrant-smuggling network centered in Brazil helped sneak illegal aliens from Middle Eastern countries to the U.S., including at least one Afghan with links to a terror plot in North America. At least a dozen Middle Easterners reached the Americas through this smuggling ring, including Palestinians and Pakistanis.

Illegal immigration to the United States can cost $400 per person. The price includes transportation, smuggling contacts, and instructions on how to cross the U.S. border illegally.

National Intelligence Director James Clapper testified in February that Islamic State terrorists would try to infiltrate the U.S. by posing as immigrants. He warned that they have already taken “advantage of the torrent of migrants to insert operatives into that flow,” and “are pretty skilled at phony passports so they can travel ostensibly as legitimate travelers as well.”

This report proves that conservative worry about terrorists posing as immigrants is indeed justified, and that Trump’s suggestion of building a wall across the southern border is less far-fetched than many thought. Even so, no one policy is a silver bullet.