A three-day sweep by police agencies across the country has led to the removal of 79 teenagers from a life of prostitution and the arrest of more than a hundred pimps, the FBI reported on Tuesday. Hundreds of FBI agents and thousands of state and local law-enforcement officers targeted the Internet as well as such places as truck stops, casinos and “tracks” where prostitutes are known to walk the street in the crackdown. The teenagers — 77 girls and two boys — ranged in age from 13 to 17. They are being held in custody until they could be placed with child welfare organizations, Reuters reported. The FBI said 104 suspected pimps were arrested during sting operations in 57 U.S. cities including Atlanta, Sacramento, and Toledo, Ohio. It was the sixth nationwide sweep — called Operation Cross Country — organized as part of the FBI’s Innocence Lost National Initiative to address the growing problem of child sex trafficking in the United States. Information gleaned from those arrested often uncovers organized prostitution rings, the FBI said. “It is clear that child prostitution and sex trafficking do not just occur somewhere else on the other side of the world,” Ernie Allen, president of the National Center for Missing & Exploited Children, a partner in the effort, said in a news release. “These insidious crimes are occurring in American cities and the victims are American kids.” The average age of a child targeted for prostitution in the United States is between 11 and 14 years old, FBI assistant director Kevin L. Perkins told the Senate Judiciary Committee in March.