Internet trolls in Russia engineered a social media campaign that targeted controversial U.S. energy projects, and appeared to be set up to upset both environmental activists and pro-oil supporters, congressional Republicans reported Thursday.

The House Science Committee report noted the Internet Research Agency, a Kremlin-linked troll farm posted thousands of times on Twitter, Facebook, and Instagram between 2015 and 2017, taking aim at the Dakota Access Pipeline, while other posts criticized the pipeline protesters.

Committee chair Rep. Lamar Smith, R-Texas, said he was not surprised the trolls had taken on both sides of the argument.

“By stirring up both sides, clearly they say that as something that could benefit them,” Smith said.

Between 2015 and 2017, there were an estimated 9,097 Russian posts or tweets about U.S. energy policy or a current energy event on Twitter, Facebook, and Instagram. During that time, there were an estimated 4,334 Internet Research Agency accounts on those three social media networks, the report said.

“The American people deserve to know if what they see on social media is the creation of a foreign power seeking to undermine our domestic energy policy,” Smith said in a statement about the report on Twitter.