However, a top Trinamool leader pointed out that the party has been traditionally strong in Kolkata, as also South Bengal. 'Where is the Congress base here? These two leaders have been winning from these seats because of their personal profile in the areas. Now they are with us. So, nobody can deny our claim.'

With Wednesday the last date for filing nomination, Mitra's wife Sikha has filed papers on a Trinamool ticket from Sealdah, while the party nominated Swarnakamal Saha from Bowbazar.

The Congress has asked Pradip Ghosh to file as a candidate from both seats, and asked Santosh Pathak to enter the fray from Bowbazar as a back-up candidate.

In case the Trinamool agrees to give one seat to the Congress, then Ghosh will contest from the constituency allotted to the party, while Pathak will withdraw.

But if the talks fail, then Ghosh will be in the race from Sealdah and Pathak from Bowbazar.

All India Congress Committee general secretary in charge of the state K. Keshava Rao however hoped the problem will be sorted out.

'Today is the last date of nominations. They have filed for both constituencies. We are also doing so. But that doesn't mean the alliance has broken. Don't come to such conclusions. Because discussions are going on, so both parties have filed nominations. There is time till the last day of withdrawal to come to an understanding,' Rao told reporters in New Delhi.

'My request to Mamataji is we are natural allies. We will work together. Let the alliance continue for ever.'

The two parties together won 25 of the 42 Lok Sabha seats in the recent polls, reducing the LF to its lowest tally of 15 seats in the last 32 years.