Updated

Recent waves of Central American immigrants arriving illegally in the U.S. have made human smuggling at least temporarily more lucrative for Mexican drug cartels, according to a U.S. Department of Homeland Security agent.

Oscar Hagelsieb, assistant special agent charge of the department's investigations unit in El Paso, told The Dallas Morning News for a Saturday report that the Gulf cartel and others in the region have "clamped their claws" into human smuggling, without abandoning their drug smuggling activities.

"We've been able to trace millions of dollars going into the Reynosa area. You cannot operate a criminal venture of that magnitude without the cartels having a major role in it," Hagelsieb said.

Guadalupe Correa-Cabrera, associate professor at the University of Texas at Brownsville, says new groups could also get involved in human smuggling, which she said has "become much more profitable."

Homeland Security chief Jeh Johnson said August 20 that more than 360 smugglers were arrested and more than $800,000 in illicit payments seized since the Immigration and Customs Enforcement agency's anti-smuggling Operation Coyote began in July.

From October to July, about 63,000 unaccompanied children were detained after entering the U.S. illegally, double the number from the same period a year earlier. Another 63,000 families – mothers or fathers with young children – were picked up during that period.

But Mexico's largest crackdown in decades on illegal migration has decreased the flow of Central Americans trying to reach the United States, and has dramatically cut the number of child migrants and families.

The Mexican government has dispatched immigration agents to scour the lines that carry the freight trains known as The Beast in an effort to discourage migrants from trying to hitch a ride to Mexico's northern border.

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