Deputy Attorney General Rod Rosenstein plans to leave Justice Department next month

WASHINGTON - Deputy Attorney General Rod Rosenstein plans to leave the Justice Department in mid-March, an official familiar with the matter said Monday night, and an announcement on his successor is expected imminently.

Rosenstein, the No. 2 Justice Department official who has spent nearly two years in the hot seat after he appointed Robert Mueller to lead an investigation into whether President Donald Trump's campaign conspired with Russia to interfere in the 2016 election, had made it known in recent weeks that he planned to leave if and when a new attorney general was confirmed by the Senate.

With William Barr's ascension to that post last week, Rosenstein has set a more precise timeline for departure - though the official stressed that his plan could shift if needed to ensure a smooth transition.

People familiar with the matter said the administration also has decided to nominate Jeffrey Rosen, the deputy secretary of transportation, to take over the job. He would need to be confirmed by the Senate, which probably would occur after Rosenstein leaves.

The news of Rosenstein's expected departure date comes as the deputy attorney general is again facing allegations from former acting FBI director Andrew McCabe that he talked about taking dramatic steps against Trump after the president fired James Comey as FBI director in May 2017. McCabe said in an interview with CBS' "60 Minutes" on Sunday that Rosenstein broached the idea of ousting Trump by using the 25th Amendment, or of wearing a wire to secretly record him in the White House.

"He said, 'I never get searched when I go into the White House. I could easily wear a recording device. They wouldn't know it was there,' " McCabe said, describing what he said Rosenstein told him. "He was not joking."

The interview sparked an angry reaction from Trump, who said on Twitter that it appeared Rosenstein and McCabe were "planning a very illegal act." The official, though, said Rosenstein's departure was expected before that, and the timeline was not affected by McCabe's recent comments.

Rosenstein has vaguely disputed McCabe's allegations. In response to the "60 Minutes" interview, a Justice Department spokeswoman said: "The deputy attorney general never authorized any recording that Mr. McCabe references. As the deputy attorney general previously has stated, based on his personal dealings with the president, there is no basis to invoke the 25th Amendment, nor was the DAG in a position to consider invoking the 25th Amendment."

The chairman of the Senate Judiciary Committee, Sen. Lindsey Graham, R-S.C., has said he wants to investigate McCabe’s assertions.