Russian President Vladimir Putin sought to help Donald Trump win the presidential election, a US intelligence report says.
The unclassified report says the Russian leader "ordered" a campaign aimed at influencing the election.
Moscow has not commented, but Russia has previously denied the claims.
After being briefed on the findings, Mr Trump stopped short of accusing Russia of interfering, saying only that the election outcome was not affected.
The 25-page report says that the Kremlin developed a "clear preference" for Mr Trump.
Russia's goals, the document added, were to "undermine public faith" in the US democratic process and "denigrate" Democratic candidate Hillary Clinton, harming her electability and potential presidency.
"We assess Russian President Vladimir Putin ordered an influence campaign in 2016 aimed at the US presidential election," it said.
The unclassified version contained no detailed evidence of Mr Putin's alleged role, but it said Russia's actions included: