A newly declassified report released on January 6 by the Office of the Director of National Intelligence said the effort sought to help Trump, a Republican, by discrediting his Democratic rival, former Secretary of State Hillary Clinton, who was widely predicted to win the November 8 contest.
"We assess Russian President Vladimir Putin ordered an influence campaign in 2016 aimed at the U.S. presidential election. Russia's goals were to undermine public faith in the U.S. democratic process, denigrate Secretary Clinton, and harm her electability and potential presidency," the 25-page report said.
"We further assess Putin and the Russian government developed a clear preference for President-elect Trump," it said. "We have high confidence in these judgments."
The report comes amid mounting alarm among policymakers and legislators in Washington about the scope and intent of Russian cyberintrusions during last year’s election campaign.
"When it appeared to Moscow that Secretary Clinton was likely to win the election, the Russian influence campaign began to focus more on undermining her future presidency," the report said.
Russian intelligence, the report said, did access some systems of state or local electoral boards. But the Department of Homeland Security concluded that the systems that were targeted or compromised were not involved in vote tallying.
The report also concluded that state-run Russian media -- including the Sputnik news agency and the international television network RT -- "contributed to the influence campaign" by promoting Trump and "serving as a platform for Kremlin messaging to Russian and international audience."
Earlier on January 6, Trump lashed out at the furor in Washington surrounding the Russian allegations, calling it a "political witch hunt."
In an interview with The New York Times, Trump said that other states or individuals could have been behind the breaches.
"China, relatively recently, hacked 20 million government names," Trump was quoted by The New York Times as saying, referring to the theft of millions of federal government personnel files in 2014 and 2015. "How come nobody even talks about that? This is a political witch hunt."
The interview was conducted prior to the report's release and shortly before he was given a classified briefing by top intelligence officials, including Director of National Intelligence James Clapper.
Trump released a statement after the meeting, which he called “constructive.”
His statement, however, did not specifically address the findings that the Russian government directed the hacks. Instead, it stated only that Russia, China, and others were "consistently trying to break through the cyberinfrastructure" of U.S. government institutions.
"There was absolutely no effect on the outcome of the election, including the fact that there was no tampering whatsoever with voting machines," Trump said.
The report also suggested that the lessons Russian intelligence officials learned from the U.S. hacking efforts were likely to be replicated in the future, possibly in key European elections scheduled for this year.
On January 5, Clapper testified before one of three Senate committees that is investigating the Russian allegations, saying that intelligence officials are even more "resolute" about their conclusions now than they were in October, when the first public assessment was released.
"I don't think we've ever encountered a more aggressive, a more direct effort to interfere in our elections processes than in this case," Clapper told the Senate Armed Services Committee.
It also expelled 35 Russian diplomats in response to what Washington calls a campaign of harassment of its diplomats in Russia.