WASHINGTON President Barack Obama is telling CIA employees they must do their work scrupulously because they are standing as a security barrier for Americans who face attack from people who have no scruples.

Obama visited the Central Intelligence Agency today, his first trip there since he released the so-called torture memos written by the Bush administration's Justice Department.

Obama said he understands intelligence officials must sometimes feel they are working with one hand tied behind their backs.

The president added that upholding American values and ideals in the face of such enemies is, as he put it, "what makes the United States special and what makes you special."

Obama has said he will not seek charges against CIA officers who took part in such tactics as waterboarding.