Facebook said on Monday that Russia-based operatives published about 80,000 posts on the social network over a two year period in an effort to sway U.S. politics, and that about 126 million Americans may have seen the posts during that time.

Facebook gave the details about the reach of Russian posts in written testimony the company provided to U.S. lawmakers which was seen by Reuters.

Executives from Facebook, Twitter and Alphabet's Google are scheduled to appear before three congressional committees this week on alleged Russian attempts to spread misinformation in the months before and after the 2016 U.S. presidential election.

The Russian government has denied any attempts to sway the election, in which President Donald Trump, a Republican, defeated Democrat Hillary Clinton.

Facebook General Counsel Colin Stretch said in the written testimony that the 80,000 posts from Russia's Internet Research Agency were a tiny fraction of content on Facebook, equal to 1 out of 23,000 posts.

The posts though violated Facebook's terms of service and any amount of such activity using fake accounts is too much, Stretch wrote.

"These actions run counter to Facebook's mission of building community and everything we stand for. And we are determined to do everything we can to address this new threat," he wrote.

The 80,000 posts were published between June 2015 and August 2017 and most of them focused on divisive social and political messages such as race relations and gun rights, Facebook said.