The deceased have been identified as Umeedh (6), Shinu (8) and Abush (6), police said.
However, the victims' brother, Shameen, who was also playing with them, managed to escape.
The incident took place at 9 am this morning when the children were alone at home as their parents had gone out for work. The house was gutted in the fire within half-an-hour.
"Umeed, Shinu, Abush were playing inside the house when the fire erupted and engulfed the entire house. Though Shameen managed to escape, the remaining three got trapped," said a senior police officer.
Meanwhile, locals said a fire engine reached the spot only after one-and-a-half hours of the incident.
"Fire tender reached the spot only when the blaze was about to douse. Despite repeated calls, they reached late," the victims' neighbour Sumit said.