Indian PM Manmohan Singh has said India will not accept any new conditions in the landmark nuclear deal with the US.
Mr Singh (left) and President Bush see the deal as crucial
Mr Singh's statement came as the US House of Representatives was to begin debating the agreement to share civilian nuclear technology with India.
The deal offers US nuclear technology to energy-hungry India in exchange for access to Indian civilian reactors.
The accord has been hailed as historic by some, but critics say it will damage non-proliferation efforts.
There have been reports in recent weeks that the US has added new conditions that include an annual review of India's nuclear policies by the US Congress.
"We will never compromise in a manner which is not consistent with the 18 July joint statement," Mr Singh told the Indian parliament, referring to the date the two sides signed the agreement last year.
US Senate and House of Representatives committees have already backed the controversial plan.
The BBC's Shahzeb Jillani in Washington says the landmark deal allowing the US to sell civilian nuclear technology to India - for the first time in three decades - is expected to be ratified by the US Congress.
US Vice President Dick Cheney has said the deal was "one of the most important strategic foreign policy initiatives of President Bush's second term".
The House of Representatives vote is part of an elaborate legislative process to clear the deal, which also has to be cleared by the 45-nation Nuclear Suppliers Group, a group of nations that exports nuclear materials, reports say.
Last month, the Senate Foreign Relations Committee and the International Relations Committee of the House of Representatives endorsed the legislation.
"[The deal] could be the most important step made in cementing a critical partnership between India and the United States," Democrat Joseph Crowley was quoted saying by Reuters news agency.
NUCLEAR POWER IN INDIA
India has 14 reactors in commercial operation and nine under construction
Nuclear power supplies about 3% of India's electricity
By 2050, nuclear power is expected to provide 25% of the country's electricity
India has limited coal and uranium reserves
Its huge thorium reserves - about 25% of the world's total - are expected to fuel its nuclear power programme long-term
Source: Uranium Information Center
The proposed agreement reverses US policy to restrict nuclear co-operation with Delhi because it has not signed the nuclear Non-Proliferation Treaty (NPT), and has twice tested nuclear weapons, in 1974 and 1998.
Mr Bush finalised the agreement during a landmark trip to India in March.
Under the deal, India's nuclear weapons sites will remain off-limits.
Critics of the deal say it could boost India's nuclear arsenal and sends the wrong message to countries like Iran, whose nuclear ambitions Washington opposes.
"By shipping India fuel for its civilian reactors, this legislation potentially frees up their [India's] entire supply of domestic uranium for use in weapons," House Democrat Ed Markey was quoted telling reporters by the AFP news agency.
India's nuclear-armed neighbour Pakistan has asked the US to address what it calls its legitimate needs in the civilian use of nuclear power.
Correspondents say there are fears the deal may spark off an arms race in South Asia with recent unconfirmed reports that Pakistan is a building new nuclear reactor to produce weapons-grade plutonium.
Energy-hungry India needs nuclear power
India's main opposition Bharatiya Janata Party has called the deal "unacceptable".
It said that it would make India "perpetually dependent" on the US for all initiatives in the application of nuclear energy.
India's Communists, who are allies of the ruling Congress-party led federal government, have also expressed their reservations about the deal.
India has made clear that the final agreement must not bind it to supporting the US's Iran policy and does not prevent it from developing its own fissile material.