Deputy Attorney General Rod J. 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 since appointing Robert S. Mueller III to lead an investigation into whether President 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 P. Barr’s swearing in to that post last week, Rosenstein has set a more precise timeline for departure — though the official stressed 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 A. Rosen, the deputy secretary of transportation, to take over the job. He will 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 steps against Trump after the president fired James B. Comey as FBI director in May 2017. McCabe said in an interview with CBS’s “60 Minutes” on Sunday that Rosenstein broached the idea of ousting Trump using the 25th Amendment, or 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 it appeared Rosenstein and McCabe were “planning a very illegal act.” The official, though, said that Rosenstein’s departure was expected and that the timeline was not affected by McCabe’s recent comments.

President Trump attacked former FBI deputy director Andrew McCabe for speaking out against Trump's "relentless attacks" on the agency. (Reuters)

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 O. Graham (R-S.C.), has said he wants to investigate McCabe’s claims.