ankara turkish warplanes strike kurdish militant target northern iraq tuesday kill three militants military say part widen campaign outlaw kurdistan workers party pkk statement military say air strike target zap region turkish name river flow across turkish-iraqi border know zab iraq air strike second tuesday third past two days since turkish soldier start military drill along iraqi border army train tank gun rocket launchers across southern border tuesday less week kurdish independence referendum northern iraq show force ahead vote reflect scale concern turkey large kurdish population region plebiscite could embolden outlaw kurdish pkk wag three-decade insurgency turkey southeast since 1984. turkish air force frequently strike pkk units mountains northern iraq group designate terrorist organization turkey unite state european union turkish warplanes kill three kurdish militants northern iraq army