WASHINGTON—The U.S. intelligence community said in a report Friday that Russian President Vladimir Putin ordered a campaign to influence the outcome of the 2016 U.S. presidential election, and that Mr. Putin aspired to help Donald Trump to victory as part of a broader ambition to undermine Western liberalism.

A declassified version of the report said U.S. intelligence concluded the Russian government wanted to undermine public faith in the U.S. democratic process and denigrate Democratic candidate Hillary Clinton, and that...