The injured have been hospitalised, police said.
The firecrackers were stored at a house in Chinnatheertham village near Veppanahalli here. The crackers burst when the children were reportedly playing with it. However, how it happened is still sketchy, police said.
"One child sustained serious injury to his fingers," police sub-inspector Govindarajan told PTI.
The injured included a 10-year-old boy and two girls, who were below 10, he said adding they were taken to the Government General Hospital here for treatment.