WASHINGTON (AP) — A Senate committee said Tuesday that U.S. intelligence agencies' assessment of Russian activities during the 2016 presidential election was based on "sound" analysis not swayed by politics.

The January 2017 intelligence assessment said Russian activities in the run-up to the presidential election represented a "significant escalation" in a long history of Russian attempts to interfere in U.S. domestic politics, the committee said.

The intelligence agencies found that Russians had engaged in cyber-espionage and distributed messages through Russian-controlled propaganda outlets to undermine public faith in the democratic process, "denigrate" Democratic candidate Hillary Clinton and develop a "clear preference" for Donald Trump.

The Senate intelligence committee's report comes as Trump continues to cast doubt on whether Russians interfered in the presidential election. Late last month, Trump tweeted: "Russia continues to say they had nothing to do with Meddling in our Election!"

The report also comes two weeks before Trump is scheduled to meet with Russian President Vladimir Putin in Helsinki, Finland.

The committee said it perused thousands of pages of documents and conducted interviews with relevant parties that helped the CIA, FBI and National Security Agency compile its review about Russian meddling.

Committee chairman Sen. Richard Burr, R-N.C., said the panel spent 16 months reviewing the sources, tradecraft and analytic work underpinning the intelligence community assessment and sees "no reason to dispute the conclusions."

"In all the interviews of those who drafted and prepared the ICA (intelligence community assessment), the committee heard consistently that analysts were under no politically motivated pressure to reach any conclusions," the committee said.

Virginia Sen. Mark Warner, the ranking Democrat on the committee, said the panel thoroughly reviewed all aspects of the intelligence agencies' work leading up to its assessment.

"The Russian effort was extensive and sophisticated, and its goals were to undermine public faith in the democratic process, to hurt Secretary Clinton and to help Donald Trump," Warner said.

Earlier this year, Republicans on the House intelligence committee concluded there was no collusion or coordination between Trump's presidential campaign and Russia. Democrats on the House panel sharply disagreed, saying the Republican-controlled panel had not interviewed enough witnesses or gathered enough evidence to make a definitive assessment.