Interior CS Kithure Kindiki assured the affected families both in Kitui and Mandera of government support.
The incident is the latest of animal-borne IED attacks in the area.
Mandera Town has been placed under high surveillance and enhanced security measures following a terror attack on Monday at the Fish Point Kiosk that led to the deaths of four people.
County Commissioner Amos Mariba said the animal came from Somalia and that its shepherd fled before the explosive detonated.