India won't agree to any changes to a nuclear cooperation deal reached with the United States last year, the prime minister told Parliament amid concerns that amendments sought by U.S. lawmakers could hurt India's interests.

"We will stick to the parameters of the agreement signed in Washington last year and this alone will be the acceptable basis of nuclear cooperation between India and the United States," Prime Minister Manmohan Singh told Parliament on Thursday.

His comments came in response to criticism by opposition parties and leftist allies who say the government is succumbing to U.S. pressures that allegedly aim to cap India's independent nuclear program.

U.S. President George W. Bush and Singh signed an agreement in July 2005 that would allow U.S. agencies and companies to sell India nuclear fuel and technology.

CountryWatch:India

In return, India would have to strengthen nuclear safeguards, allow international inspections of its civilian facilities, and separate its civilian and military nuclear programs.

However, opposition parties and Singh's own communist allies are seeking assurances that India's nuclear program would not be curbed by what they describe as the shifting of goal posts by American legislators.

The U.S. House of Representatives approved the deal last month but added stringent new clauses, including requiring annual certification on the use of the technology and fuel for peaceful purposes.

India will not accept or allow "external supervision" of its research and development work in the nuclear field of its strategic programs, Singh said.

"We have made it clear that India's strategic program is outside the purview of the agreement, " Singh said. "These are complex negotiations to put in place new rules, and there will be pulls and pressures. However, India will not succumb to those pressures."

Singh's lengthy defense of the nuclear deal, followed angry speeches from opposition leaders denouncing the nuclear agreement.

"From the start we have opposed the agreement. We have never been in doubt about the deleterious impact of this deal," said Yashwant Sinha, a former foreign minister belonging to the main opposition Bharatiya Janata Party.

Other lawmakers expressed concern about the new clauses that have been introduced in the terms of the agreement by U.S. lawmakers, including a threat to revoke the deal if India conducts a nuclear test.

However, Singh assured lawmakers that India would not agree to any crucial changes being introduced into the agreement at this stage.

The U.S. Senate is expected to vote next month on the civilian nuclear plan. The vote will be followed by several other legislative and diplomatic steps before the treaty can be enforced.