US authorities rescued 52 children, including one as young as 10, from prostitution rings and arrested nearly 700 people during a nationwide sting operation over the weekend, the FBI said Monday.

The three-day push in 36 US cities "led to the recovery of 52 children who were being victimized through prostitution" and the arrest of close to 700 others, "including 60 pimps, on state and local charges," the Federal Bureau of Investigation said.

"Child prostitution continues to be a significant problem in our country, as evidenced by the number of children rescued through the continued efforts of our crimes-against-children task forces," said Kevin Perkins, assistant director of the FBI's Criminal Investigative Division.

The roundup, which officials said took place over the previous 72 hours, was part of a larger FBI program called "Innocence Lost," whose task forces have removed nearly 900 children from the streets since 2003, convicted 510 people and seized 3.1 million dollars in assets, the FBI said.

Agents targeted truck stops, casinos, street corners and websites as part of their hunt for offenders.

"They target areas known to have prostitution," FBI special agent Jason Pack told AFP. "When they find young looking ones they try to find ways to engage the folks and go from there," he said.

The youngest person taken off the street was a 10-year-old girl in the midwestern United States. The other 51 were mostly females under age 18, he said.

The FBI said initial arrests for solicitation typically uncovered larger, more organized efforts to prostitute women and children across the United States.

"It is repugnant that children in these times could be subjected to the great pain, suffering, and indignity of being forced into sexual slavery for someone else's profit," said assistant attorney General Lanny Breuer of the Criminal Division.

The roundup however "has shown us that the scourge of child prostitution still exists on the streets of our cities."