Dozens of people on five continents have been arrested and charged with making and trading child pornography.
U.S. Attorney General Eric Holder made the announcement Wednesday at a news conference in Washington, D.C.
The arrests are the result of a 20-month international investigation into a child pornography ring that operated through a private, members-only website called Dreamboard, according to authorities.
At least 600 individuals were targeted in the probe with 72 charged in the United States. Of those, 52 Americans have been arrested. Arrests have also been made in 13 other countries.
Dreamboard members are accused of sexually abusing children, producing images and videos of the abuse, and sharing the images and videos with other members of the website.
Authorities said that in order to maintain their membership, participants were required to continually upload images of child sexual abuse.
Holder said many of the victims were under 12 years old and included infants.
“The members of this criminal network shared a demented dream to create the preeminent online community for the promotion of child sexual exploitation but for the children they victimized, this was nothing short of a nightmare," Holder said. "This operation marks another important step forward in our work to protect children across -- and beyond -- this country. Our nation's fight to protect the rights, interests and safety of children goes on, and it will continue to be a top priority of this Justice Department."