Facebook estimates that around 60 million or 2 percent of its monthly average users may be fake accounts, according to a report from the company.

Many of the false accounts are used for spam, Facebook CFO Dave Wehner said in a recent investors call.

Separately, Facebook estimates that around 10 percent of its accounts are "duplicate" accounts, meaning they are accounts run by a user separate from their main account. This would amount to more than 200 million accounts.

Facebook, Twitter and Google testified before the Senate Intelligence Committee in a three-day session this week, providing investigators information on the efforts of foreign actors to meddle in U.S. politics.

One of the investigators' concerns, according to The New York Times, is the widespread use of "fake" social media accounts.

Twitter also reports that nearly 5 percent of its user base, or more than 16 million accounts, are fake "spam" accounts, Sean Edgett, the social media giant's acting general counsel, said in testimony.

Some of those “fake” accounts may be duplicate or false accounts. Facebook has consistently struggled to police such accounts — which include accounts for pets or accounts using a fake name — in an attempt to verify users.

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The tech company testimonies come amid a wide-ranging investigation into foreign meddling in the 2016 election, and Moscow-based propaganda aimed at influencing its outcome.

The general counsel for Facebook told committee members that the company was doubling its in-house staff focused on reviewing accounts and would use artificial intelligence to find more fraudulent accounts.

Russia-linked Facebook accounts were found to have encouraged politically-motivated violence in the U.S. during the contentious 2016 election. Facebook also revealed during testimony this week that the Kremlin-linked ad campaign reached about 146 million Americans.

CORRECTION: An earlier version of this story misstated the number of fake accounts that Facebook estimates are used on its platform.