Washington, Dec 13 (IANS): US Under Secretary of Defence for Policy Michele Flournoy has decided to quit the job, the Pentagon said Monday.

"Flournoy has today announced her intention to step down and return to private life. In her discussions with me, Michele made clear that her decision to leave is motivated by personal and family considerations," Defence Secretary Leon Panetta said in a brief statement.

Flournoy, the highest-ranking female at the Pentagon, has agreed to stay on until early next year to enable a smooth transition, Xinhua reported quoting the statement.

Confirmed by the Senate in February 2009, Flournoy is responsible for all matters on the formulation of national security and defence policy, the integration and oversight of Pentagon policy, and plans to achieve national security objectives.

"Michele has been an invaluable advisor to me during my six months as secretary of defence, and has been an outstanding departmental leader for nearly three years at a time of great consequence for our nation's defence," Panetta said.