"Everybody knows that the CBI is the Congress Bureau of Investigation and CPI(M) Bureau of Investigation," Mamata Banerjee told a party rally here.
"If any attempt is made to take action against those who protested against forcible land acquisition, the people will protest," she warned.
Mamata Banerjee, who did not refer to the CBI charge-sheet, alleged that it was made to meet certain interests.
The charge-sheet was submitted by the CBI in a court in Haldia a few days ago on the investigation into the firing on March 14, 2007 at Nandigram in East Midnapore district which left 14 people dead.
It said that the police fired 10 rounds on the instructions of an executive magistrate, contradicting TMC claim then that the order was given by the police.
The charge-sheet said that the firing was on an unlawful assembly of people who threw stones at the police.
The charge-sheet also said that efforts were made by the East Midnapore district administration to normalise the situation, but the entire area remained cutoff from the civil and police administration.
The charge-sheet kicked off a political storm in the state with the opposition Left Front lashing out at the TMC.
The CPI(M), which lost much of its support base because of Nandigram agitation, hailed the CBI charge-sheet as a clean chit to then chief minister Buddhadeb Bhattacharjee.
"It has been proved that it was a campaign against the Left regime. The gathering was illegal and with ill motive," CPI(M) politburo member Surya Kanta Mishra, who is the Leader of the Opposition, said.
"The allegation that the firing was ordered on the instructions of then chief minister Buddhadeb Bhattacharjee is baseless," Mishra said, adding police followed standard operating procedure before opening fire that was ordered by an executive magistrate present at the spot.