Seth was arrested on the charges of abduction and murder of seven anti-land acquisition agitators in Nandigram.
"In deference to the people's mandate in the Haldia civic body poll, we demand release of Lakshman Seth and other leaders, who have been held in jail custody, by the state government," a CPI-M party release said.
The party also demanded that Trinamool Congress workers immediately stop terrorising opposition party cadres in Panskura, Durgapur and Haldia.
