The Congress on Tuesday ignored the suggestion that former prime minister P V Narasimha Rao could emerge as a possible challenger to party chief and prime ministerial candidate Sonia Gandhi.

"We don't react to every comment," was the curt reply of chief spokesman S Jaipal Reddy when asked by rediff.com to respond to the suggestion that had come from Nationalist Congress Party leader and former Lok Sabha speaker Purno S Sangma.

"She has no challenger. Therefore, you are asking an irrelevant question," he said.

Sangma had said that Rao was the only 'match' for Prime Minister Atal Bihari Vajpayee. He had also said his party was ready for an alliance with the Congress if Sonia stood down as the opposition prime ministerial candidate.

His suggestion might have gladdened the hearts of Sonia baiters, but all prominent Congress leaders have stood by her.

Sangma took a cue for his suggestion from the former railway minister and senior Congress leader C K Jaffer Sharief who during a function in Bangalore on Monday said that the Congress chief was not the best bet as the opposition prime ministerial candidate.

Sangma's controversial contention also focussed attention on his party whose chief Sharad Pawar welcomed his Congress counterpart's assertion that the people would decide on the opposition prime ministerial candidate.

Reddy, however, clarified that Sonia was the party's prime ministerial candidate, implying that she was the most suitable for the slot among the secular opposition.

Despite Bharatiya Janata Party chief M Venkaiah Naidu and his party colleagues' dig at Sonia on the issue of the opposition prime ministerial candidate, party sources told rediff.com that there was disquiet in the leadership over the Congress-Dravida Munnetra Kazhagam tie-up.

DMK chief M Karunanidhi has said he saw no roadblocks in the way of an alliance between his party and the Congress.

The BJP sources pointed out that while the DMK and the MDMK exit from the ruling National Democratic Alliance combine did not shake the stability of the Vajpayee government, it was a 'worrisome' development.

This was because with the BJP upbeat following its decisive victory in the assembly polls, it felt that it would face little competition in forming the government after the 2004 general election.

But with indications that the Congress, DMK, MDMK and the Communist Party (Marxist) could form a front, which could spill over to the national level, the BJP had reasons for worry, they said.

Besides parties like the NCP were waiting in the wings to see how the potential tie-up between the Congress and the DMK-MDMK combine shaped up.

They also pointed out that 'preserving' the BJP's 'feel good' factor (following its victory in Congress-ruled states Madhya Pradesh, Rajasthan and Chhattisgarh) till the general election among the electorate was an uphill task.