Russian content on Facebook, Google and Twitter reached far more users than companies first disclosed, congressional testimony says.

Facebook plans to tell lawmakers on Tuesday that 126 million of its users may have seen content produced and circulated by Russian operatives, many times more than the company had previously disclosed about the reach of the online influence campaign targeting American voters.

The company previously reported that an estimated 10 million users had seen ads bought by Russian-controlled accounts and pages. But Facebook has been silent regarding the spread of free content despite independent researchers suggesting that it was seen by far more users than the ads were.