A group of MGNREGS workers were digging soil in a field at Madhyapara of West Tripura district and the bomb, hidden inside the soil, exploded when it was hit by a spade.
"Of the three injured labourers, the condition of one of them was stated to be serious. All the injured were admitted to Agartala Government Medical College. Some miscreants might have kept it inside the earth," IG Police Control, Nepal Das said.
The police are investigating the case.