In an analysis of the earlier campaign, which Facebook took down in May, the Washington think-tank the Atlantic Council called the operation the "Secondary Infektion."

"The operation was strongly reminiscent of the Soviet-era 'Operation Infektion' that accused the United States of creating the AIDS virus," according to an Atlantic Council blog post at the time. "The latest operation ... used a similar technique by planting false stories on the far reaches of the internet before amplifying them with Facebook accounts run from Russia."

The Atlantic Council said the size, scope and sophistication of the effort suggested it was developed by an intelligence operation.

Reddit said Friday that it confirmed "a pattern of coordination" that linked the recent suspicious post on its platform to the much larger campaign on Facebook. Suspicious accounts on Reddit linked to the post "have the same shared pattern as the original Secondary Infektion group detected, causing us to believe that this was indeed tied to the original group."

The company said it banned one "subreddit" discussion forum and 61 accounts as a result of its investigation.