The Left blames its political rival, the ruling Trinamool Congress, for that assault and the violence today. Left leaders allege that stones were hurled at some buses while bullets were fired at others at Bamunghaata, just 30 kms from Kolkata.
Local channels showed vans on fire and injured people being brought to hospital.
Trinamool leader Mamata Banerjee, the chief minister of West Bengal, was unwell today but rushed to her office at Writers' Building this afternoon to chair an emergency meet after the violence erupted. After that session, minister Partha Chatterjee said the CPM instigated the violence when its workers en route to Kolkata attacked Trinamool leader Arabul Islam. When asked who set the buses on fire, he responded, "First let me find out who attacked Arabul."
Arabul Islam according to the Left, led an attack on Sunday on a former minister from the CPM, Rezzak Mollah. Today's rally had been called to demand Mr Islam's arrest.