The supporters of CPI(M) and Congress clashed at Islampur village under Domkol sub-division while campaigning for the panchayat polls.
They hurled bombs at each other and also used firearms, Superintendent of Police of Murshidabad Humayun Kabir said.
The injured have been admitted to Murshidabad Medical College Hospital, the sources said, adding, condition of three of the injured was serious.
Eight persons have been arrested in this connection, the SP said, adding, police reinforcements have been rushed as there was tension in the area.