Pakistan : They were arrested for having supported a polio vaccination campaign , he says . The case is in the volatile tribal Khyber Agency . Pakistan is the sole country in the world where cases so far this year exceed last year 's toll .
NEW : They were kidnapped for having supported a polio vaccination campaign , official says . The school is in the volatile tribal Khyber Agency . Pakistan is the sole country in the world where cases so far this year exceed last year 's toll .