Senior officials have rushed to the spot to hold talks with the irate tribals.
An assistant sub-inspector and three 'chowikars' were held while they were returning from the district headquarters to Barhara police station, District Magistrate N Shrawan Kumar said.
The tribals were protesting administrative action against them for encroaching on the land at Parora village, he said.
They had encroached on 100 acre of land, of which 82.5 acre belonged to the Milia Educational Trust.
