Janata Dal-United leader Nitish Kumar said the National Democratic Alliance's (NDA) prime ministerial choice should be secular and acceptable to everyone - an obvious comment on Modi.

"The NDA will have to declare its nominee. The electorate should know who they are voting for and who will lead the country. The NDA should have a leader who can feel for the underdeveloped states like Bihar," the chief minister said in his interview to the Economic Times.

"This leader should be acceptable to every constituent of the alliance. To me, the leader of the coalition should have secular credentials... In a multi-religious and multi-lingual country like ours, the leader should not have rough edges in his personality. An alliance can win the confidence of the people only if the leader is seen as accommodating," he said.

While the Bharatiya Janata Party kept mum, its alliance partner Shiv Sena came out in support of UPA presidential candidate Pranab Mukherjee, exposing the cracks within the NDA.

Sena leader and Rajya Sabha MP Bharatkumar Raut also told IANS Tuesday that the NDA should name its prime ministerial candidate.

"We feel that the NDA should take this step but only after consultation with all the parties in the alliance," Raut said.

The BJP has maintained that the prime ministerial candidate will be announced only after the Lok Sabha elections. But Modi had been projecting himself for the post.

Asked by reporters in Patna about his comments to the Economic Times, Nitish Kumar quipped: "Golden words are not repeated again."

Nitish Kumar's interview ignited a war of words in Bihar between the two allies -- the BJP and JD-U.

Bihar's Deputy Chief Minister and BJP leader Sushil Kumar Modi added to the drama by saying that the NDA's prime ministerial candidate would be picked by the NDA and not the BJP - and that India needed a liberal like Atal Bihari Vajpayee.

Amid the tensions, Rashtriya Janata Dal leader Lalu Prasad posed a question for Nitish Kumar.

"If Modi is communal, he (Nitish Kumar) should tell us which leader in the BJP has secular credentials," he said in Patna.

The Congress had reasons to rejoice.

"We are a secular country, so our prime minister must be secular," Law Minister Salman Khurshid said.

In the same breath, he took a dig at the Bihar chief minister.

"Nitishji has said the Indian prime minister should be secular, I am hundred percent in agreement.

"But why does Nitish Kumar have fears that the Indian prime minister will not be secular, I am not able to understand," he said.

Punjab Chief Minister Parkash Singh Badal added: "Whatever decision will be taken will be taken jointly by NDA."