The clash took place yesterday when Ramgopal and his group attacked Hukum Singh and his associates with sticks and started firing at them in order to stop the ploughing of a disputed agricultural field, they said.
Singh is a police constable posted in Aligarh district, they said.
Ramgopal and Satish, belonging to one group and Bobby (Hukum's son), Mohit and Rambesh from the other group, were injured in the incident, police said.
The injured were rushed to a hospital for treatment, they said, adding counter FIRs were registered on the complaints of both the groups.