JACKSONVILLE, Fla. -

A nationwide crackdown on child sex trafficking last week led to the arrest of one man described as a pimp in Jacksonville, and 26 people on prostitution charges.

They are among 281 people arrested across the country.

While none of those found in northeast Florida were juveniles, the FBI said Monday that the operation rescued 168 victims of child sex trafficking, many of whom had never been reported missing.

IMAGES: FBI photos of NE Florida arrests

Eight juveniles were recovered and three people labeled pimps were arrested in the Tampa area and three children were located and four were arrested on sex trafficking charges in the Miami area.

Nationwide, 281 people the FBI identified as pimps were arrested.

"These are not faraway kids in faraway lands," FBI Director James Comey said in announcing the annual enforcement push known as Operation Cross Country. Instead, he added, "These are America's children."

This is the eighth such week-long operation, which this year unfolded in 106 cities. The FBI says nearly 3,600 children have so far been recovered from the street.

"I hate that we have to do this work -- hate it," Comey said. "I love the people who've devoted their lives to doing this work. There is no more meaningful work that the FBI participates in than rescuing children."

He said the operations were designed to "crush these pimps" and show that children are not for sale. They are also intended to rescue children who are being trafficked on street corners, in truck stops and, increasingly, on the Internet, where pimps advertise and arrange sexual encounters.

Drugs, firearms and money were also seized during the crackdown.

One challenge, officials said, is that many of the children who were recovered were never reported missing in the first place -- by parents, guardians and the entire child welfare system designed to protect them.

"No one is reporting them missing. Hence, no one is looking for them," said John Ryan, CEO of the National Center for Missing and Exploited Children. "But for operations like this, these children likely would never have been found."

He said better laws were needed to require child welfare service to report children who disappear. Right now, he said, only two states have laws requiring agencies to report children missing from their care. There is no national, uniform standard.

"We cannot find them if no one reports them missing," Ryan said.

Though this operation is the FBI's eighth of its kind, Comey said this year featured the highest number of participating cities. He said the biggest change was the increasing prevalence of children being sold online rather than on street corners.