A Congress-led alliance comprising seven smaller parties was launched in Kolkata on Sunday to take on the ruling Communist Party of India (Marxist)-led Left Front and Mamata Banerjee's Trinamool Congress in the coming assembly polls in West Bengal.

The formation of the alliance, named United Democratic Alliance, came a day after the state Congress president and Defence Minister Pranab Mukherjee's announcement that the party will contest the majority of the 294 seats in the state, virtually ruling out chances of any poll adjustments with the Trinamool Congress.

"Today, we have launched the United Democratic Alliance in line with the United Progressive Alliance at the Centre. We will fight the upcoming polls jointly," Mukherjee told reporters after a meeting with the leaders of the new alliance partners.

Besides the Congress, the constituents of the alliance are Saifuddin Chowdhury-led Party for Democratic Socialism, a breakaway group of CPI(M), Republican Party of India, Indian People's Front, a breakaway group of Forward Bloc, Ram Vilas Paswan's Lok Janashakti Party, United Communist Party of India, Shibu Soren's Jharkhand Mukti Morcha and Jharkhand Party (N).

The constituents will fight the polls on a common minimum programme, which will highlight what it will do if it was voted to power, Mukherjee said, adding however that the constituents will have separate poll manifestos.