The condition of one of the children was serious, said police. The incident occurred in Birnagar area under Kaliachak police station, about 330 km from here, in Malda district.
An injured child said they were playing and saw some "balls" when they opened the door of the house. "And then there was an explosion."
Malda police superintendent Kalyan Mukherjee said the family members suspected bombs were thrown from outside. "However, we are not in a position to say anything conclusive as the probe is on", he said.
Forensic experts have also been summoned.
"As per the complaint, the children were playing in the courtyard when their mothers heard the sound of an explosion. They rushed and found the children were injured," Mukherjee told mediapersons.
A part of a finger of one of the children was found in an icecream box.
All three were rushed to the Malda Medical College and Hospital.
An injured child's mother said: "The incident happened just after we returned home after voting. The children were playing. We suddenly heard an explosion and rushed in to see them lying injured."
Trinamool leader ansd state Tourism Minister Krishnendu Narayan Chowdhury said: "Bombs were hurled at the house from outside." He blamed the Congress for the incident.
The fourth phase of the violence-ridden panchayat polls is being held Monday in Malda, Murshidabad, Birbhum and Nadia districts. Malda is a traditional Congress stronghold.
--IANS (Posted on 22-07-2013)