"Congress does not believe in negotiating leadership," party spokesman Anand Sharma told media persons in New Delhi when asked whether the party would be ready to reconsider Singh's name for the top job if the Left put up condition for his removal to gain its support.
Sharma said government-formation was a game of numbers and "we are making it clear to our partners that they must not delude themselves on this. No secular government is possible without the Indian National Congress".
The Congress rejection of the suggestion has come at a time when there has been speculation that Left parties could put up conditions like removal of Singh as the leader.
However, the Communist Party of India-Marxist general secretary Prakash Karat on Tuesday ruled out any truck with the Congress after the elections.
The Left parties and Singh are not on the best of terms for the past one year after the key outside supporters withdrew support to his government accusing the Prime Minister with 'betrayal' on issue of the Indo-US nuclear deal.
The party also reacted sharply to Bharatiya Janata Party's charge that Manmohan Singh was a "stop-gap" PM accusing the saffron party of resorting to cheap gimmicks and personalised attacks against the Dr Singh in the absence of any national agenda.
