NEW DELHI (Agencies) - India's main Hindu nationalist Opposition Thursday demanded Prime Minister Manmohan Singh quit, accusing him of misleading parliament over a key nuclear pact with the US. The deal, which seeks to allow India to buy nuclear technology and reactors after a gap of three decades, has sparked many stormy debates since it was clinched in 2006. The fresh controversy was triggered by a report in The Washington Post that said the United States would cut supplies of nuclear fuel and end all cooperation if New Delhi tested atomic weapons. Secret correspondence from US President George Bush, in which he has told the US Congress that the US will not sell sensitive nuclear technologies to India and would immediately terminate nuclear trade if New Delhi conducts a nuclear test, was unveiled by Howard L Berman, Democrat member of the House of Representatives from California who is also the House Foreign Affairs Committee Chairman. A spokesperson for Berman briefed The Washington Post on the matter, which carried a report on Thursday. The facts are contained in the US Administration's 26-page reply to questions raised by Congress on the Indo-US Civil Nuclear Agreement. The clarifications were sent to Berman's predecessor, the late Tom Lantos, on January 16 this year. According to the Bharatiya Janata Party (BJP), that position contradicts Manmohan's assurances to parliament that the pact would not affect India's right to test atomic weapons. "The State Department disclosures have confirmed our worst fears... It is now crystal clear that India will lose the right to conduct nuclear tests forever as a result of this agreement," senior BJP official Yashwant Sinha said. "This is a gross breach of privilege of parliament. The BJP demands that a session of Parliament be convened in the shortest possible time so that we can move a breach of privilege motion against the Prime Minister." "This government has no business to continue in office," Sinha said. However, US Ambassador to India David C Mulford said the letter "contains no new conditions and there is no data in this letter which has not already been shared in an open and transparent way with members of the Congress and with the Government of India". Meanwhile, the United States inched towards a deal Thursday in its efforts to persuade nuclear supplier nations to lift a 34-year-old embargo on trade with India, a diplomat at negotiations said. "One of the representatives said that a deal was 'within reach'," the diplomat told AFP, speaking on condition of anonymity at the closed-door meeting of the Nuclear Suppliers Group (NSG). The diplomat declined to predict how soon that might be. Earlier, US delegation head, Under Secretary of State for Political Affairs William Burns, had insisted Washington was making progress. "I believe that we're making steady progress in this process and that we'll continue to make progress," Burns told reporters. Washington has tabled an amended paper to the NSG, addressing some of the concerns of opponents. "The new exception was designed to meet some of the concerns raised at the last meeting," the diplomat said. Daryl Kimball, non-proliferation expert and executive director of the Washington-based Arms Control Association, called the revised proposal "unsound and irresponsible" and called on the NSG to reject it. "The revised US proposal does not incorporate any meaningful adjustments or concessions and is essentially the same as the earlier draft proposal," Kimball said.