US vows CIA will not stage fake vaccine programs, amid backlash over use in hunt for Osama bin Laden

The White House has promised the United States will not use vaccination programs as cover for spy operations - after the move was attempted during the hunt for Osama bin Laden in Pakistan.

As Pakistan suffers a resurgence of polio, a top White House official pledged in a letter dated May 16 that intelligence agencies would foreswear the tactic, which is partly blamed for the spread of the crippling disease.