US President Barack Obama's national security advisor James Jones is retiring and will be replaced by his hard-charging deputy Tom Donilon, senior officials said on Friday.
Two senior officials revealed the decision by Jones, the latest step in a wide-ranging White House shake-up, on condition of anonymity.
The departure of Jones had been expected by the end of the year, amid speculation that the retired general and former NATO commander was unhappy at not being seen as a member of Obama's inner circle.
Jones played a major role in the Afghan strategy review run by Obama into Afghanistan and Pakistan policy last year and racked up thousands of miles pushing US diplomacy abroad.
The latest announcement came just a week after White House chief of staff Rahm Emanuel stepped down to run for Chicago mayor and followed a series of other departures.