A three-day U.S. crackdown on child prostitution resulted in 104 arrests, the FBI said.

The operation, conducted June 21 to June 23 in 57 cities, rescued 79 children as young as 13 years old being held against their will and forced to work as prostitutes, said Kevin Perkins, an FBI official, at a briefing today for reporters in Washington.

This is the sixth nationwide operation targeting child prostitution coordinated by the Federal Bureau of Investigation since 2008, Perkins said.