Deputy Attorney General Rod Rosenstein will brief all U.S. senators Thursday on the ouster of James Comey.
Senate Majority Leader Mitch McConnell announced that the briefing will take place at 2:30 p.m., ET.
The White House initially cited a scathing memo Rosenstein wrote about Comey's handling of the Hillary Clinton email investigation last year as part of its justification for firing Comey. However, Trump later told NBC News that he would have fired the FBI director "regardless" of what the Justice Department said.
Comey's ouster — and how the administration explained its timing — raised questions, as the FBI is probing Russian meddling in the 2016 election and any possible ties between the Trump campaign and Moscow.
Reports have indicated that Rosenstein expressed concerns about how the Trump administration portrayed his role in Comey's termination. But the deputy attorney general denied reports that he threatened to quit over the White House's handling of the Comey firing.
Senate Minority Leader Chuck Schumer had called for a briefing from Rosenstein, and he and McConnell invited the deputy attorney general last week. After Trump's comments to NBC, Schumer said "the need for these briefings is even greater."
Separately, House Democratic leader Nancy Pelosi called Monday for Rosenstein to brief the full House.