Congressional investigations into Russia’s role in the 2016 U.S. presidential election are looking at the spread of misinformation on a number of online services — not just Facebook.

In fact, Twitter is meeting with Congressional staffers today. Recode’s Tony Romm says Twitter’s Vice President of Policy Colin Corwell is currently in a closed-door meeting with the Senate Intelligence Committee.

According to Politico, Senate investigators are going to be asking questions about how tweets contributed to news coverage, how tweets may have driven up Google rankings of fake news and, “What, if anything, did Twitter do to address bots once it had identified them as potentially malicious?”

In addition, a number of publications have reported that the Senate Committee is asking Facebook, Twitter and Google to testify at a hearing on November 1.

Most of the recent discussion around Russia’s online activity has focused on Facebook (among other things, this has prompted Facebook to announce new transparency measures around ad-buying), but new research suggests that Russia is quite active on Twitter, too.

For example, the Alliance for Securing Democracy says that since last month, it has been following 600 Twitter accounts — some operated by bots, some by humans — tied to Russian operations. They’re not, however, simply supporting President Donald Trump. In fact, in the recent controversy around Trump and N.F.L. players, the accounts ended up posting messages on opposing sides of the debate.

There’s also new research from Oxford University which found that 20 percent of tweets sampled from around the election included “polarizing and conspiracy content,” including content from Wikileaks and Russian sources. The greatest concentration of that content was in swing states like New Hampshire, Pennsylvania and North Carolina.

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