© Chip Somodevilla/Getty Images North America/Getty Images Former acting Director of National Intelligence Joseph Maguire testifies before a House Select Committee in 2019 regarding the whistleblower complaint.

Former acting Director of National Intelligence Joseph Maguire has formally resigned from US government service, a source familiar with the matter tells CNN.

The office of DNI also officially announced the second-ranking official there, Andrew Hallman, stepped down Friday afternoon.

President Donald Trump became irate in a meeting with Maguire last week for allowing lawmakers to be briefed about the intelligence community's belief that Russia is already taking steps to interfere in the 2020 election with the goal of helping Trump win, a White House official has told CNN.

On Wednesday, Trump announced he was naming Richard Grenell, a staunch loyalist and current US ambassador to Germany, as acting DNI despite him not having experience in intelligence.

Democrats are raising fresh concerns about the appointment of Grenell, who does not have intelligence experience, and whether he was moved into the role in reaction to Trump's anger toward Maguire over the briefing.

"Now all of a sudden, senior people in the intelligence community may be thinking that if I give honest intelligence — if I can take you back, you know, 15 years or so, 20 years, there are no weapons of mass destruction, President George W. Bush — that my career might suffer," Rep. Jim Himes, a Connecticut Democrat, said on CNN's "New Day." "And when that happens, this country is in a very, very bad place."

Trump on Thursday evening said another close ally, GOP Rep. Doug Collins of Georgia, was under consideration to be his permanent director of national intelligence, but Collins, who is running for Senate against GOP Sen. Kelly Loeffler, said Friday morning on Fox News he did not want the job.

Last week's briefing, led by election security official Shelby Pierson, was fairly comprehensive about Russia's meddling efforts, sources familiar with the matter said. In the briefing, the intelligence community briefer said twice that the IC's observation is that Russia has a preference for Trump, one of the sources said.

"The briefers were not ambiguous about the Kremlin having a preference for Trump," said the source, while underscoring that intelligence briefers never say anything is clear -- they simply provide an assessment.

Republicans pushed back on the assessment.

Rep. Will Hurd, a Texas Republican, asked House Intelligence Committee ranking member Rep. Devin Nunes for some time for questioning, and pressed the briefer about what led to that statement and how many intelligence reports it was based on.

The briefer responded that they did not have the underlying data, just the assessment, the source said.

This story has been updated with additional background information.