peshawar pakistan militant pakistani taliban group say carry attack sunday kill five people tribal areas border afghanistan tehreek-e-taliban pakistan ttp spokesman mohammad khurassani say militants plant improvise explosive device target security personnel bajaur agency area part federally administer tribal areas fata blast strike vehicle mamund area bajaur kill four security personnel official civilian administration local government source say bajaur one pashtun tribal regions near afghan border security region improve recent years pakistani military mount offensives al qaeda-linked pakistani taliban consider country big security threat militants continue stage attack fata remain off-bounds foreigners consider one volatile part nuclear-armed nation 208 million people pakistani taliban say behind deadly blast tribal region