A 14-year-old boy lost one of his fingers and injured his left palm when crude bombs went off in a mango orchard behind a Trinamul Congress office in North 24-Parganas on Sunday morning.

The bombs were kept in a bag and Arman Ali mistook them for balls. The bombs exploded as he began playing with one.

The incident occurred in the Sekher More area of Kalsur gram panchayat, a strong domain of Trinamul.

Alerted by the deafening sound of the blast, local people rushed in and took the boy to nearby Biswanathpur rural hospital, where he was admitted with multiple injuries.

Later, separate teams from Eganga and Chakla police stations combed the area and found at least three more bombs. A bomb squad was also informed about the discovery of the explosives.

The incident has meanwhile ignited a political blame game with Trinamul accusing the ISF and the BJP of the blast.

Trinamul panchayat member Sahabul Sardar alleged that criminals with close proximity to the BJP and the ISF had planned to attack the ruling party and stockpiled the bombs. “But the bombs were accidentally found by a boy and he began playing with one of them when the blast took place. The Opposition, particularly the ISF leadership, has become desperate to attack us,” said Sardar.

Both the ISF and the BJP rejected the charge.

The BJP’s Barasat organising district president, Tarunkanti Ghosh, said: “Criminals enjoying the patronage of the ruling party have begun stockpiling bombs ahead of the Lok Sabha polls. People across the state live on the stockpile of bombs, which everybody knows well. Unfortunately, the police knew it all but had little power to act.”

The Deganga police registered a case and started a probe.

Last week, three children had been injured in a similar blast at Farakka.