Mamata Banerjee advised the BJP to concentrate on working for the country (File Photo)

West Bengal Chief Minister Mamata Banerjee Wednesday accused the BJP of indulging in horse-trading in Karnataka and claimed that rebel Congress lawmakers of the southern state were locked up in Mumbai.

Claiming that Constitution is in danger, the Trinamool Congress president said, "We condemn this arrogant attitude (of the BJP)."

"We just got to know from the media that Congress MLAs are locked up. They are preventing media from entering the area. The BJP is trying to indulge in horse-trading," Ms Banerjee said at the Assembly premises.

She alleged that mediapersons were not allowed where the Congress lawmakers are locked up and some agencies were helping the ruling party at the Centre.

"Democracy will lose if horse-trading continues," the Trinamool Congress chief said, adding, "Our constitution is in danger, our federal structure is in danger. It's a constitutional break down."

"We support the regional parties and others... fighting for democracy," Ms Banerjee said.

In a fresh jolt to the wobbly Congress-JDS coalition government in Karnataka, two Congress legislators, Housing minister MTB Nagaraj and K Sudhakar, tendered their resignations Wednesday to the Speaker, taking the number of disgruntled lawmakers who have quit to 16.

The development comes even as state water resources minister DK Shivakumar, who is the Congress' troubleshooter, was detained and sent packing back to Bengaluru from Mumbai, where he was prevented by police from meeting the rebel lawmakers.

The coalition faces the threat of losing majority in the Assembly if the resignations are accepted as its current tally is 116 in the 224-member House.

Ms Banerjee advised the BJP to concentrate on working for the country instead of "trying to topple" state governments run by parties opposed to it.

"I do not understand why they are so greedy. Why they are in such a hurry to capture all states. This is dirty politics. After Karnataka, they (the BJP) will turn to Madhya Pradesh, Rajasthan. Is it their job to break governments?" she posed.

Wondering whether the country was heading towards a Presidential form of governance, the chief minister said all parties and media should unite and fight the BJP.