"It is a matter of concern. I do not know whom to blame for it. Last night I have spoken to West Bengal Governor to take all possible measures to stop violence there, because violence cannot be tolerated", Chidambaram told reporters here.
"There were three incidents after the election was over. I have also spoken to Mamata Banerjee and Mukul Roy about the violence and appealed to all political parties to stop violence. I think they would respond to my appeal", he added.
The union home minister also appealed to the Maoists to abjure violence and start peace talks.
"84 percent people have exercised their franchise which means that people are not in favour of any kind of violence in the state. I also appeal to the Maoists to abjure violence and start peace talks", he said.