Vice President Bhairon Singh Sekhawat, who is tipped to be the presidential candidate backed by National Democratic Alliance on Friday refused to be drawn into any discussion on the issue.

"Let us not discuss it (presidential polls)," he said when asked to comment on UPA's choice of Pratibha Patil for the Presidential election.

Shekhawat, who administered oath to Prime Minister Manmohan Singh [Images] and another newly elected member from Assam to the Rajya Sabha, declined to answer any questions on the issue.

When Dr Singh took oath, UPA chairperson Sonia Gandhi, was also present.

However, neither Dr Singh nor Sonia Gandhi answered any questions from mediapersons on the presidential polls.

Both Dr Singh and Sonia had on Thursday night spoken to senior Bharatiya Janata Party leader Atal Bihari Vajpayee over phone seeking NDA's support for UPA's nominee.

Though NDA has not officially nominated any candidate for the post, Vajpayee, who is its chairman, has rebuffed efforts of Sonia and Dr Singh to seek the opposition support for the UPA nominee.

The Congress leaders were rebuffed by the opposition leader who said the request has come "too late" and that the opposition alliance was "unable" to back their candidate.