CNN reported that senior intelligence officials gave Trump a summary of the allegations to make him aware that the information had been circulating among some lawmakers, government officials and journalists.
In excerpts of an interview with Lester Holt of NBC Nightly News scheduled to air Friday, Obama said he wouldn't comment on classified information. The president said he ordered a report by U.S. intelligence agencies on Russian hacking during the 2016 campaign to help prevent it from happening again.
"My expectation and my hope is that this work will continue after I leave," Obama said in the interview. "That Congress in possession of both the classified and unclassified reports, that the president elect and his administration -- in possession of both the classified and unclassified reports -- will take it seriously and now get to work reinforcing those mechanisms that we can use to protect our democracy."
Shortly before the election, FBI director James Comey had announced that his agency was re-opening an investigation of emails sent by Hillary Clinton while she was secretary of state -- a disclosure she and her aides blame for contributing to her loss. Then-Senate Democratic leader Harry Reid wrote Comey and demanded that he disclose information in the FBI's possession about Trump's connections to Russia.
A former aide to Reid confirmed that the senator knew about the memos published Tuesday before sending his letter to Comey. The issue arose again during a hearing Tuesday on the Russian hacking and extending sanctions. Democratic Sen. Ron Wyden of Oregon asked Comey whether the FBI has investigated reported relationships between individuals in Trump's campaign and Russian officials. Comey said he couldn't comment "in an open forum like this."
Democrats began seizing on the memos late Tuesday.
"The intelligence dossier presents profoundly disturbing allegations; ones that should shake every American to the core," Neera Tanden, a Clinton ally who is the president of the Center for American Progress, a Democratic-aligned research group, said in a statement. "They must be fully investigated. The charges levied in this dossier of, among other things, conspiring with a foreign power are extremely serious and call into question whether Trump can be trusted to defend America."
Before last week's briefing by intelligence officials, Trump had expressed skepticism that Russia was responsible for hacks of Democratic Party officials' email accounts during the campaign. The U.S. intelligence community has concluded that Putin ordered the hacking as part of a scheme to tilt the election toward Trump.
Republican and Democratic senators joined to offer legislation on Tuesday that would impose mandatory visa bans and freeze U.S. assets of individuals who carry out cyberattacks on significant public or private infrastructure or on democratic institutions. Top intelligence officials also reaffirmed their finding that they had "high confidence" of Putin's involvement in the hacking at the hearing by the Senate Intelligence Committee on Tuesday. The hacking was aimed at undermining Clinton and then helping Trump, they said.
They did not assess the "impact on the electorate," they said.