NEW DELHI, Sept 4 India`s Left Front and the rightist Bharatiya Janata Party (BJP) demanded the resignation of Prime Minister Manmohan Singh on Thursday after a supposedly secret letter by the Bush administration on the India-US nuclear deal revealed stiff conditions that New Delhi had claimed did not exist.

Both groups accused the prime minister of misleading parliament in a recent trust vote, which he won with difficulty amid charges of bribing MPs. The 45-member Nuclear Suppliers Group is meeting in Vienna to consider its crucial response to the Indo-US deal.

“If these disclosures had been made before July 22, 2008, the Manmohan Singh government would have lost the trust vote. Thus, the Singh government has no business to continue in office and should leave immediately,” former foreign minister Yashwant Sinha told a news conference at the BJP office here.

Mr Sinha added that in view of the “gross breach” of privilege of both the Houses of Parliament, an immediate session should be convened “within the shortest possible time”.