Additional Superintendent of Police Shafiul Haque said the village head Suraj Yadav of Sirala panchayat and his three supporters were arrested after an incident of shoot-out at Rambigha village.
Their arrest sparked off violent protest by locals who started demonstrating before the police station.
As the situation went beyond control, police opened fire in self-defence, Haque said.
The situation was tense but under control.