The Trinamool Congress supremo, surrounded by her ministers and top party leaders, stayed up the entire night on a makeshift dais at the city hub Dharamtala area, near the Metro Channel, after starting the demonstration around 9 p.m. on Sunday.

There is a blanket security cover in the area.

"This is a Satyagraha and I'll continue till the country is saved," Banerjee told the reporters here.

The Chief Minister said she was getting calls from politicians, including former Uttar Pradesh Chief Minister Akhilesh Yadav, Madhya Pradesh Chief Minister Kamal Nath, Delhi Chief Minister Arvind Kejriwal, all of whom expressed their support for her action.

Nanda reached the venue in the morning as representative of party chief Akhilesh Yadav.

Meanwhile, the Trinamool Congress supporters held protest demonstration and put up rail and road blocks in various parts of the city and districts.

A large number of party activists also arrived at Dharamtala since early in the day to express their solidarity.

In an unprecedented confrontation between the Narendra Modi-led central government and the West Bengal government, Banerjee began the sit-in accusing Modi and Bharatiya Janata Party chief Amit Shah of attempting a coup to destabilise her state, saying there is a "constitutional break-down", after an ugly face-off between the CBI and the state police.

The showdown started after the federal probe agency's officers showed up near the residence of Kolkata Police Commissioner Rajeev Kumar, who has been under the scanner in connection with the Central Bureau of Investigation probe into the ponzi scheme scam case.

The events were expected to cast a shadow on the Budget Session of Parliament on Monday with the opposition expected to vociferously raise the issue.