Russian interference in the 2016 U.S. presidential election on social media was more widespread than previously thought and included attempts to divide Americans by race and extreme ideology, said reports by private experts released on Monday by U.S. senators from both parties.

The Russian government's Internet Research Agency, based in St. Petersburg, Russia, tried to manipulate U.S. politics, said the reports, one by social media analysts New Knowledge and the other by an Oxford University team working with analytical firm Graphika.

The twin reports largely verified earlier findings by U.S. intelligence agencies, but offered much more detail about Russian activity going back years that continues even now, said the reports and senior lawmakers.

For instance, one Russian troll farm tried to encourage U.S. "secessionist movements" in California and Texas, the New Knowledge report said.

"This newly released data demonstrates how aggressively Russia sought to divide Americans by race, religion and ideology," said Richard Burr, the Republican chairman of the U.S. Senate Intelligence Committee, in a statement.

The Russian agency worked to erode trust in U.S. democratic institutions and its activities have not stopped, he said. The committee collected data from social media companies that was used by the private analysts in their analysis.