Washington, D.C. ? More than 600 adults have been arrested and 47 children rescued in a three-day roundup targeting people who force children into prostitution.

The FBI said the roundup by federal, state and local law enforcement occurred in 29 cities, adding that the raids dismantled 12 large-scale prostitution operations run through call services, truck stops, casinos and Web sites.

At a news conference announcing the results of Operation Cross Country II, FBI Deputy Director John Pistole said the arrests were made possible by intelligence gathered during a similar series of raids in June.

“Sex trafficking of children remains one of our most violent and unconscionable crimes in this country,” Pistole said.

The 47 rescued children ranged in age from 13 to 17, and all but one are female. Of these, Pistole said, 10 had been reported to the National Center for Missing and Exploited Children.