Lawyers representing nearly 800 former Boy Scouts have filed a lawsuit alleging the youth organisation failed to prevent hundreds of sex abuse cases.
The lawsuit identifies 350 abusers who were not listed in Boy Scouts of America (BSA) files, claiming the group was negligent in vetting volunteers.
The suit's plaintiff, only identified as SD, alleges a scout leader assaulted him "hundreds" of times in the 1970s.
The Scouts have apologised and said reporting procedures have changed.
Speaking at a news conference on Tuesday, lawyer Tim Kosnoff said: "This will sound hyperbolic, but it's sex trafficking. It's the largest paedophile ring on earth."
----------
It accuses BSA of knowing "for decades that sexual predators of boys had infiltrated scouting" and that children like SD were at risk,
the Washington Post reported.
BSA told the BBC in a statement that they believe and support victims and pay for counselling, and when they received information from Abused in Scouting attorneys, they "immediately investigated the limited information provided" and have reported 120 cases to state law enforcement agencies.
"We are continuing to manually search paper records at the local level to see if we can identify more information about the additional alleged perpetrators identified in the plaintiff's attorneys list."
"The BSA has taken significant steps over many years to ensure that we respond aggressively and effectively to reports of sexual abuse," the statement added.
"We recognise, however, that there were instances in our organisation's history when cases were not addressed or handled in a manner consistent with our commitment to protect Scouts, the values of our organisation, and the procedures we have in place today."
Beginning in February, when reports emerged that BSA was considering filing for bankruptcy, Abused in Scouting used television ads to reach Boy Scouts across the country.
Hundreds of members and former members allegedly began coming forward, which Mr Kosnoff said on Tuesday is still a "miniscule proportion" of the total number of victims.
