Top US intelligence officials say Russia poses a major and growing threat to US government, military, diplomatic and commercial operations - as well as America's critical infrastructure.
National Intelligence Director James Clapper and other intelligence officials are testifying at a Senate Armed Services Committee hearing focused on Russia's alleged meddling in the US presidential election.
They say Russia is among at least 30 nations that are developing capabilities to launch cyber attacks.
President-elect Donald Trump has expressed scepticism that Russia was behind the election hacking.
US intelligence agencies disagree.
The officials are not expected to disclose details of a report on foreign influence in US elections before President Barack Obama gets a briefing on that report on Thursday.
- AP