The Associated Press reports the Senate Intelligence Committee has formally requested that more than a dozen organizations, agencies, and individuals preserve all material related to Russian interference in the 2016 election.
AP on February 18 cited information from a congressional aide who was not authorized to discuss the matter and spoke on condition of anonymity.
AP said committee chairman Senator Richard Burr, a Republican from North Carolina, and vice chairman Mark Warner, a Democrat from Virginia, sent out the letters making the request on February 17.
Committee members that same day received a classified briefing from FBI chief James Comey.
Committee members declined to comment on what was discussed in the briefing.
On February 17, Republican Senator Marco Rubio of Florida expressed confidence in the Senate's ability to investigate Russia's hacking of U.S. organizations during the campaign.
"I am now very confident Senate Intel Comm I serve on will conduct thorough bipartisan investigation of #Putin interference and influence," Rubio tweeted.