The federal law enforcement officers found the children between Aug. 31 and Sept. 4 as part of an emergency operation around Indianapolis, Indiana, the service said.

The children are between the ages of 6 and 17, and they were handed over to the Indiana Department of Child Services.

“These children … were considered to be some of the most at-risk and challenging recovery cases in the area, based on indications of high-risk factors such as victimization of child sex trafficking, child exploitation, sex abuse, physical abuse and medical or mental health conditions,” the U.S. Marshals said.

They added that officers were given case files and investigated their whereabouts starting with addresses, homes, and schools.

“The Marshals are committed to assisting state and local agencies with locating and recovering endangered missing children to help prevent their falling victim to crimes of violence and exploitation,” said Dan McClain, the U.S. Marshal for the Southern District of Indiana. “The message that we wish to convey to the missing children and their families is that we will use every resource at our disposal to find you.”

Over the past several weeks, there have been operations under different names to find missing children around the United States.

Last week, around 39 missing children were located in a two-week rescue operation in Georgia, according to the U.S. Marshals.

Director of the U.S. Marshals Donald Washington said in a statement: “The message to missing children and their families is that we will never stop looking for you.”

In a press conference announcing the news, Washington told reporters that the operation is among the missions that the Marshals are “very proud of” but “that we wish we didn’t have.”

“As successful as this operation was there is a harsh reality here—the harsh reality is, ‘gee, why are we doing this in the first place? Why do we have missing, endangered children?’” he said. “The stats are that in every 40 seconds, there is a child abducted in the United States.”

The operation, a culmination of several months of planning, was carried out by the U.S. Marshals’ Service Missing Child Unit and its Southeast Regional Fugitive Task Force, as well as a number of Georgia state and local agencies, including the Georgia Bureau of Investigation, and the National Center for Missing and Exploited Children.

So far, more than 70 children have been found in recent weeks.

Mimi Nguyen-Ly contributed to this report.