Secretary of State Warren Christopher's top, hand-picked aide for policy planning resigned Friday.

Although Christopher and Samuel Lewis heaped praise on each other in an exchange of letters, the State Department has been rife with rumors for weeks that Lewis felt out of the loop in high-level decisionmaking.In addition, Lewis spent several days in intensive care two months ago after an automobile accident and is said to be in fragile health.

Lewis, a career foreign service officer who held several posts in the Middle East, came out of retirement to join the Clinton administration.

He is the sixth State Department official and the third among Christopher's inner circle to resign.

Four Balkan desk officers and the refugee bureau's director, who was ambassador in Belgrade when the war began, resigned in protest of the Clinton administration's inability to stop the bloodbath.