NATO troops on Saturday handed control of Afghanistan's northern capital Mazar-i-Sharif to local forces amid rising security fears just days after it was hit by a deadly bombing. Mazar-i-Sharif is the sixth of seven areas to transition to Afghan control, but critics say the timetable is politically motivated and skepticism is running high over Afghan abilities to ward off a trenchant Taliban insurgency. Underscoring the threat, a suicide bomber killed four people in the city on Wednesday, in an attack that the provincial police chief said was carried out "to create chaos and disrupt the transition of security". Until recently considered one of the safest Afghan cities, Mazar-i-Sharif was thrown into turmoil in April when demonstrators, protesting against the burning of a Koran by a U.S. pastor, attacked a UN compound and killed seven foreign staff.