Dec. 17 (UPI) — Facebook, Twitter and Google impeded in the Senate investigation into Russian meddling in the 2016 U.S. presidential election, a new report said Monday.

The report was compiled by Britain’s University of Oxford and analyzed by the firm New Knowledge. It said the tech companies submitted incomplete data and misled lawmakers about the actions of Internet Research Agency, a Russian troll farm.

The Computational Propaganda Research Project done by the University of Oxford said the Russian agency used social media to polarize the United States from 2012 to 2018 — including campaigns to encourage African-American voters to boycott elections and Hispanic voters to distrust U.S. institutions. The propaganda, it said, encouraged extreme right-wing voters to be confrontational. The trolls also sent sensationalist, conspiratorial and other forms of junk political news and misinformation to voters across the political spectrum to get spark outrage and division, the report said.

“Russia’s Internet Research Agency (IRA) launched an extended attack on the United States by using computational propaganda to misinform and polarize U.S. voters,” the report states. “In this analysis, we investigate how the IRA exploited the tools and platforms of Facebook, Instagram, Twitter and YouTube to impact U.S. users.”

“Regrettably, it appears that the platforms may have misrepresented or evaded in some of their statements to Congress; one platform claimed that no specific groups were targeted (this is only true if speaking strictly of ads), while another dissembled about whether or not the Internet Research Agency created content to discourage voting (it did),” the report said. “It is unclear whether these answers were the result of faulty or lacking analysis, or a more deliberate evasion.”

A Facebook spokesperson said the company has been fully cooperative with the Russian probe.

“We’ve provided thousands of ads and pieces of content to the Senate Select Committee on Intelligence for review and shared information with the public about what we found,” the Facebook spokesperson said. “Since then, we’ve made progress in helping prevent interference on our platforms.”

A Twitter spokesperson said in a statement, “Our singular focus is to improve the health of the public conversation on our platform, and protecting the integrity of elections is an important aspect of that mission.” It added the company has made strides since 2016 to prevent the “manipulation of our service.”

The propaganda campaign reached an estimated 126 million people on Facebook, generated another 10.4 million tweets on Twitter, more than 1,000 videos to YouTube and 20 million users on Instagram.