James Martin/CNET

Facebook is delving deeper into possible Russian interference in the US election.

The social network said Wednesday it sold $100,000 worth of ads to inauthentic accounts likely linked to Russia during the election. The ad spending was from June of 2015 to May of 2017 and associated with roughly 3,000 ads.

"Our analysis suggests these accounts and Pages were affiliated with one another and likely operated out of Russia," Alex Stamos, Facebook's chief security officer, wrote in a blog post.

Facebook said it's continuing to investigate the issue and reported its findings to US authorities.

Most of the ads and accounts didn't have to explicitly do with the election or either of the then-candidates, Hillary Clinton and Donald Trump. Instead, they were focused on divisive political topics, including LGBT issues, immigration and gun rights.

The disclosure on Wednesday is a stark turnaround from CEO Mark Zuckerberg's comments days after the election. He said at the time it was a "crazy idea" that Facebook influenced the election.

Since then, Facebook has taken a harder stance on false news on the social network. The company changed its advertising policies to make sure publishers didn't make money from false stories. Facebook has also started working with third-party fact-checkers.

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