At a public meeting in Kolkata on Wednesday evening, Chief Minister Mamata Banerjee said, "If there is any trouble at Gangasagar, the annual Hindu pilgrimage in Bengal, you will be responsible, you who are doing all kinds of conspiracies," Ms Banerjee said, without naming the BJP.
"Thirty lakh people have come for Gangasagar mela but they only want to do mischief and conspiracies against Bengal," she added.
Ms Banerjee's outburst came soon after the Calcutta High Court gave the BJP permission for a bike rally across Bengal to mark 12 January. BJP's youth wing had proposed a motorcycle rally from south to north Bengal.
West Bengal police have said no, citing a huge gathering at the annual pilgrimage at Gangasagar now underway.
"The bike rally will start tomorrow as planned," said Debjit Sarkar, head of the BJP youth wing. "We are not going anywhere near Gangasagar. The rally will mark the birth anniversary of Swamiji's and Sister Nivedita. It is also a protest rally against lawlessness in Bengal, especially women's safety," he said.
Dilip Ghosh, BJP's Bengal chief, directly attacked Ms Banerjee at a public meeting at Sodepur. "Mamata Banerjee and her government have been slapped by the court again, like many times in the past. If she had any self-respect, she would have resigned by now after being upbraided by court so often," he said.
Ms Banerjee, in her address, also questioned why the centre did not declare national holidays on the birth anniversary of Swami Vivekananda and Netaji Subhash Chandra Bose, which is on 23 January.
"Why hasn't the centre declared Swamiji's birth anniversary a national holiday? Also, why not Netaji Subhash Chandra Bose's birthday on 23 January? But what can you expect from people who have stopped a holiday on Christmas?" the chief minister said.
Prime Minister Narendra Modi has visited the headquarters of the Rama Krishna Mission at Belur in Bengal several times and has often said he is a disciple of Swami Vivekananda.
"But what have they done?" Ms Banerjee said. "We have given money to Belur Math, we are building a skywalk at Dakshineswar Temple. They have done nothing," she said.