Five persons, with bullet injuries, were taken to the Khulna Rural Hospital following the clash in Sandeshkhali's Halderbheri where bombs and guns were used, they said.
"This is a political clash. 16 BJP activists and four TMC workers were injured in it but we have not detained anybody," a senior police official said.
Police from the Sandeshkhali police station and a team of RAF were rushed to the spot to take control of the situation.
"The situation is under control now but we have posted RAF to keep a check," the officer added.