A longtime FBI deputy director who had been expected to replace Director Christopher Wray on an acting basis is retiring from the bureau.

Paul Abbate, the deputy director of the FBI who took over temporarily as acting director after the resignation of Christopher Wray, retired from his post on Monday, an FBI official said.

Paul Abbate made the unexpected announcement in an email to senior officials Monday ahead of President Trump's inauguration.

Brian Driscoll, who has worked for the Federal Bureau of Investigation (FBI) since 2007, has been named the acting director of the agency. The news came after Paul Abbate retired.

FBI Deputy Director Paul Abbate retired from his post minutes after President Trump was sworn into office. Mr. Abbate, who was a key member of the leadership team that critics say politicized FBI culture and investigations,

Paul Abbate, who as the FBI's longtime deputy director had been expected to replace Director Christopher Wray on an acting basis, is retiring from the bureau, according to an email he sent to senior executives and obtained by The Associated Press on Monday.

President Trump has promised a monumental shift within the FBI with a major change in leadership at the very top after former Director Christopher Wray and acting director Paul Abbate resigned.