Facebook's Instagram played a much bigger role in Russia's manipulation of U.S. voters than the company has previously discussed, and will be a key Russian tool in the 2020 elections, according to a report commissioned by the Senate Intelligence Committee.

Russian Internet Research Agency, the troll farm that has sought to divide Americans with misinformation and meme content around the 2016 election, received more engagement on Instagram than it did on any other social media platform, including Facebook, according to a joint report by three groups of researchers. "Instagram was a significant front in the IRA's influence operation, something that Facebook executives appear to have avoided mentioning in Congressional testimony," the report says. IRA activity shifted there after the media began to write about Russian activity on Twitter and Facebook. "Our assessment is that Instagram is likely to be a key battleground on an ongoing basis."

There were 187 million interactions with Instagram content, compared with 77 million on Facebook and 73 million on Twitter, according to a data set of posts between 2015 and 2018, analyzed by New Knowledge, Columbia University and Canfield Research.

Facebook said in a statement that it has provided thousand of ads to lawmakers and made progress in preventing interference during elections. Twitter said it too has made significant strides in countering manipulation of its service and pointed to the release of additional data in October to enable further research and investigation.

The fact that Instagram outperformed Facebook for the IRA could "be an indicator of the platform being more ideal for memetic warfare" — changing people's minds using viral memes. Instagram is organized by interest and hashtags, and is based on photos and videos more than text. It could also mean the IRA used click farms to boost their numbers.

Facebook has given Instagram only passing mention in its disclosures about Russian activity on its platform. At the company's first congressional testimony on Russian influence last November, it didn't include Instagram in its count of how many Americans were reached by Russian content until specifically asked. The photo app has a relatively untarnished brand.

Still, the researchers said, IRA content sparked conversation, with the overall goal of emboldening followers of Donald Trump and criticizing Hillary Clinton, sometimes in subtle ways. About 40 percent of the Instagram accounts achieved more than 10,000 followers, and 12 had over 100,000 followers. The biggest account, blackstagram, attracted 303,663 followers. Another account promoted the idea that Clinton was a bad ­feminist.

"Although the Facebook operation received more attention in the mainstream press, more content was created on Instagram, and overall Instagram engagement exceeded that of Facebook," the paper states.

Exploiting racial tensions

Those Russian efforts also focused on exploiting racial tensions to suppress voter turnout among minorities, a campaign that proved more far-reaching and effective than previously understood.

The activities of Russian operatives and their messages in which they often posed as black activists have been known for some time, but the new reports reveal extensive additional detail about how that operation spread such threads of misinformation far and wide.

"The most prolific IRA efforts on Facebook and Instagram specifically targeted Black American communities and appear to have been focused on developed Black audiences and recruiting Black Americans as assets," said one of the reports, from the research firm New Knowledge.

The Los Angeles Times contributed to this report.