At least 10 people were injured in a clash between the supporters of Awami League-nominated candidate and his rebel candidate ahead of the by-election to Lankhanpur Union Parisad in Sharsha upazila.
The incident took place Wednesday night.
Awami League-backed candidate Anowara Khatun's supporters were attacked by rebel candidate Kamal Hossain's supporters around 11pm at Bahilaputa village, said Mashiur Rahman, officer-in-charge of Sharsha police station.
The attackers exploded several crude bombs and used local weapons during the clash that left Mehdi Hassan Shipon, Al-Amin, Mission, Mana, Ripon, Shamim, Hafizur, Rubel, Kadua, Laltu and Aizel injured.
They also vandalised eight motorcycles. The injured were rushed to Sharsha Upazila Health Complex from where seriously injured four were shifted to Jessore General Hospital.
A case was filed with the police station in this connection, the OC said.