According to police, Maoists triggered the landmine blast at Topchanchi town of the district when security personnel were patrolling.
"Five policemen have been injured in the landmine blast," Jharkhand police spokesperson S.N. Pradhan told IANS.
The injured have been hospitalised, with condition of two of the injured being serious. Maoists are active in 18 of the Jharkhand's 24 districts.