Media playback is unsupported on your device Media caption Hundreds of men say they were abused in the Boy Scouts

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."

The suit was filed on Monday in Pennsylvania by three law firms in the group Abused in Scouting.

Image copyright CBS Image caption Lawyer Mr Kosnoff described BSA as cult-like

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."

Media playback is unsupported on your device Media caption Why it can take sexual assault allegations years to come out

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.

Mr Kosnoff said BSA leaders were "entrusted with your boys to go out in the woods, away from their parents, overnight, in circumstances where they're totally exposed".

He added that the group has a "quasi-military structure" which can be beneficial to youth, but was also "the perfect setting for child molesters".

The lawsuit's plaintiff, 57-year-old SD, claims in the criminal complaint that his Scout master in Pennsylvania "actively groomed young boys under his charge for later sexual molestation".

He claimed when he was 12 or 13 years old, he suffered "hundreds of instances" of sex abuse, the Post reported.

Image copyright Getty Images Image caption Boy Scouts walk around a campsite

The lawyers allege they have identified 350 men, like SD's alleged abuser, who were never named in the Boy Scouts' internal files, according to Mr Kosnoff. He added the names would not be released until the claims were investigated further.

He also accused BSA of not properly keeping documents on perpetrators, called "ineligible volunteer" files, saying there was a "haphazard, willy nilly destruction" of those records over the decades.

"The kind of numbers we're talking about now dwarf what we've seen in the Catholic Church cases," Mr Kosnoff claimed.

Abused in Scouting also alleges BSA tried to cover up cases or handle them "discretely" by encouraging abusers "to voluntarily resign and move on".

The lawyers said most victims - ranging in age from 14 to 88 - came from California, Texas and Florida, and that some states like North Carolina had "disproportionately large" numbers.

The case is expected to go to trial in two to three years, according to the lawyers.

BSA is one of the largest youth nonprofits in the US, with millions of members. The group has faced numerous sex abuse lawsuits over the decades.