Mamata wanted the chief minister to own up responsibility for the Nandigram killings and step down, leaving enough indications that she will maintain her defiant stance till the panchayat polls.

"I can't go for talks with a person who has no credibility and who is responsible for loss of lives in Nandigram. He has to resign," Mamata said amid applause from a huge gathering that stalled the traffic at Esplanade for quite a few hours.

The Trinamul chief urged her supporters to take on CPM politically. Calling this strategy "Operation CPM", Mamata said: "We need to fight them tooth and nail, or else they will get us. Are you ready for an intense political battle?" The crowd roared to voice their assent.

With an eye on next year's panchayat election, the Trinamul chief asked her followers to start the groundwork now. "We need to organise political workshops at the grass-roots level. I know CPM is trying to hatch a conspiracy before the Haldia polls. They don't believe in political courtesy," Mamata said.