Seven persons were injured in a clash between Communist Party of India-Marxist and Trinamool Congress supporters at Simulkundu village in Nandigram on Saturday evening, the police said.
Police rushed to the spot. Two persons, stated to be CPI-M supporters were arrested.
The police also recovered 12 crude bombs during a raid on the house of a CPI-M local leader Ajay Raut at Baruna village during the day.
According to the police, the bombs were concealed in a drum and were later defused.
Police said more raids would follow.