33 missing children found in anti-human trafficking operation in Southern California

(CNN) Thirty-three missing children were recovered this month in an anti-human trafficking operation led by FBI's Los Angeles field office, the bureau said in a statement Friday.

Of the 33 children recovered during "Operation Lost Angels," eight were being sexually exploited at the time of their recovery, the FBI said. The operation began on January 11.

Two children were recovered multiple times during the operation, the FBI said, noting it's not uncommon for rescued victims to return to commercial sex trafficking "either voluntarily or by force, fraud, or coercion."

"This harmful cycle highlights the challenges victims face and those faced by law enforcement when attempting to keep victims from returning to an abusive situation. Victims may not self-identify as being trafficked or may not even realize they're being trafficked," the FBI statement said.

Some of the other victims located during the operation were sexually exploited in the past and were considered vulnerable missing children, the statement said.