The incident occurred at a house in Swat district in the Khyber Pakhtunkhwa Province of Pakistan.
The explosion took place in the Bashigram area of Tehsil Madyan in Swat district. The toy bomb killed a local resident and his two kids while three children of the same family were injured, police said.
The injured were taken to a hospital nearby.
The children found the toy outside their house and brought it inside. They were playing with the toy when it suddenly exploded, family members said.