The top U.S. general in South America says that about 100 recruits have left the Caribbean to join ISIS in Syria.

Marine Gen. John F. Kelly told the Senate Armed Services Committee that ISIS and Iran are recruiting in nations like Jamaica, Trinidad and Tobago.

He warned that these ISIS fighters could return to the Caribbean and use smuggling networks to get into the United States.

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“No one checks their passports,” the general said. “No one, you know, they don’t go through metal detectors. No one cares why they’re coming. They just ride this network.“

More than 15,000 foreign fighters have poured into the Middle East to join the Islamic State, traveling primarily to Syria. Kelly, who oversees U.S. military operations in Central and South America and the Caribbean, acknowledged that the number of fighters coming from his region is small, but said that the countries involved don’t have the ability to monitor those returning well.

“I would suspect … that while they’re in Syria they’ll get good at killing and they’ll pick up some real job skills in terms of explosives and beheadings and things like that,” Kelly said. “Everyone is concerned, of course, if they come home because if they go over radicalized, one can expect that they’ll come back at least that radicalized, but with really good job skills.”

John Bolton, former U.S. ambassador to the U.N., said on tonight’s “On the Record” that the attraction to the ISIS ideology is hard to understand.

“If we don’t understand we’re fighting an ideology, we’re not gonna understand its appeal, we’re not gonna be able to defend against it,” Bolton said.

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