In a four-day nationwide operation aimed at sex trafficking, the Federal Bureau of Investigations says it had rescued 84 minors, and arrested 120 people.

The 11th annual Operation Cross Country was coordinated by the FBI Omaha Child Exploitation Task Force and the National Center for Missing and Exploited Children (NCMEC) and involved 55 FBI field offices, 78 state and local task forces and several international partners, according to an FBI statement.

"The youngest victim recovered during this year's operation was 3 months old, and the average age of victims recovered during the operation was 15 years old," the bureau said of the operation which ran from Oct. 12-15.

Reuters reports that the 3-month old and a 5-year-old, both girls, were offered to an undercover officer for $600. The person trying to sell them was a friend of the family, the news agency says.

"Historically, kids would be recruited in face-to-face environments, at malls and at bus stops or in schools or in and around foster homes," Staca Shehan, executive director of the NCMEC's case analysis division, was quoted by Reuters as saying. "All that stuff happens, but now what we see more often than not is kids are recruited online, and they're controlled online and sold online."

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