Three Communist Party of India (Marxist) activists were killed and five injured in a bomb blast in Nandigram where a bandh was being observed on Sunday at the call of an organisation spearheading movement against land acquisition for industries.

Two party offices of the CPI(M) were torched and a car carrying Congress leaders attacked allegedly by CPI(M) workers in Nandigram during the bandh called by Bhumi Uchhed Pratirodh Committee (BUPC).

Three CPI(M) activists were killed and five injured in an explosion near CPI(M)'s relief camp at Sherkhan Chowk in Khejuri area of Nandigram block on Saturday night, Inspector General of Police (law and order) Raj Kanojia said in Kolkata.

Ashok Guria, member of the Krishak Sabha, peasants' wing of the CPI(M), claimed that BUPC members hurled bombs in the party's relief camp at Sherkhan Chowk in Khejuri area killing three men.

However, BUPC core committee member Sabuj Pradhan said the blast took place when they were making bombs at Khejuri, a stronghold of the CPI(M).

During the bandh called by the BUPC to protest the clash yesterday that claimed the life of one person, BUPC workers torched two CPI(M) party offices, including a zonal office, at Nandigram busstand.

They also set afire a heap of CPI(M)'s flag in front of the Nandigram police station.

Meanwhile, district Youth Congress secretary Milan Pradhan alleged that a vehicle carrying Congress leaders from Kolkata was attacked by CPI(M) workers at Fullir More.

The car was carrying Chandrima Bhattacharya, women's wing president of the state Congress, and three other PCC leaders.

Meanwhile, Trinamool Congress chief Mamata Banerjee has started for Nandigram from district headquarter Tamluk, Trinamool sources said.