The policemen were on patrol duty on Jorhat-Mariani road under Cinnamora out-post of the district when the vehicle in which they travelling hit a tree while trying to save a herd of cows who strayed into the road.
Jorhat Superintendent of Police Amanjeet Kaur said the three, all constables, received severe head and chest injuries and have been admitted to the Jorhat Medical College Hospital.
The police has so far rounded up 22 cows found straying on roads since morning and kept them in a cow shed owned by Cinnamora Gaon Panchayat and a fine will be imposed on owners who allow the animals to stray.