The incident occurred at around 1:30 pm when the Nagaland State Transport bus ferrying people from a marriage party fell into the gorge killing 11 persons on the spot while two succumbed to injuries on the way to Phek district hospital, police said.
The deceased include six males and seven females.
Another 21 people sustained severe injuries and were rushed to Phek Civil Hospital.
Chief Minister T R Zeliang has condoled the death of 13 people in the bus accident.
In a message, he expressed shock and sorrow at the loss of so many precious lives and prayed that the Almighty would grant solace to the bereaved families.
The Chief Minister also wished speedy recovery to the injured persons.
