Mamata Banerjee, after saying she would try to attend Prime Minister Narendra Modi's oath ceremony in Delhi on Thursday as a constitutional duty, pulled a 180-degree today saying: "Please excuse me". The Chief Minister, in a curt letter posted on Twitter, referred to the BJP's allegation that 54 of its workers had been killed in political violence in Bengal and called it "completely untrue".

"The ceremony is an august occasion to celebrate democracy, not one that should be devalued by any political party that uses it as an opportunity to score political points," Mamata Banerjee wrote in her RSVP.

The BJP today said it had invited - following a decision taken by PM Modi and Amit Shah last night -- the families of workers allegedly killed in Bengal over the last six years. That apparently triggered Mamata Banerjee's change of mind and a sharp retort.

That the families were special invitees at the ceremony was seen as a blunt message for the Bengal Chief Minister. The BJP alleges its workers were killed during Panchayat or local body polls and the national election. With the invitation, the party said, it wants to convey to its cadre in Bengal that the central leadership cares and stands by them against "violence by Trinamool Congress workers".

Hours after the BJP's move came Mamata Banerjee's acrid response.

"Congratulations, new Prime Minister Narendra Modi ji. It was my plan to accept the 'constitutional invitation' and attend the oath-taking ceremony. However, in the last one hour, I am seeing media reports that the BJP are claiming 54 people have been murdered in political violence in Bengal. This is completely untrue. There have been no political murders in Bengal," said the Chief Minister, adding that the deaths may have taken place due to personal enmity, family quarrels and other disputes, "nothing related to politics".

"So, I am sorry, Narendra Modi Ji, this has compelled me not to attend the ceremony," she wrote.