The Senate intelligence committee says it agrees with intelligence reports that Russia intervened in the presidential election won by Donald Trump in 2016.
The committee stated that "the Russian effort was extensive, sophisticated, and ordered by President Putin himself."
The announcement came a year after Washington first began to investigate possible Russian collusion.
"The Russians did play a role in trying to interfere, not only with our elections in 2016, but with the British French and German elections as well," Republican Senator Susan Collins, who is a member of the Senate intelligence committee, said.
Democrat Senator Mark Warner, another intelligence committee member, concurred.
"The Russians massively intervened in our elections to the purpose of helping Mr. Trump and hurting Hillary Clinton. They also used social media in ways that were unprecedented," he said.
US Special Counsel Robert Mueller's investigation is focusing on a meeting between Donald Trump's son Donald Junior and Nataliya Veselnitskaya, a Russian lawyer and acknowledged Kremlin informant.