Seeking quick implementation of the civil nuclear agreement, the US has said it will be "tragic" for India if it forgoes this opportunity for a strategic partnership with the US.

"We believe it is essential to quickly implement the landmark civil nuclear agreement with the United States and bring India into the international nuclear non-proliferation mainstream,'' US Under Secretary of Commerce for International Trade Christopher Padilla said on Monday.

"It will be tragic for India to forgo this opportunity for a strategic partnership with the United States," he said. Washington has been insisting that India needs to complete the processes required for the deal, saying time was running out in the light of the Presidential elections later this year.

New Delhi needs to firm up a safeguard agreement with the International Atomic Energy Agency (IAEA) and secure changes in the guidelines of the 45-member Nuclear Suppliers' Group (NSG) to enable international nuclear commerce with it. But stiff opposition from Left allies has tied the government's hands in moving fast on the deal.

Addressing a Heritage Foundation seminar, Padilla said, "The benefits for India are clear, and we hope that India's government will choose to move forward as quickly as possible to fully realise the potential of this historic agreement".

Padilla said India is the world's fourth largest energy consumer and will be the third largest by 2030.

The country's high rate of economic growth and its growing middle class have placed additional demands on an already strained power sector.

It would need to add about 160,000 MW of new capacity in the next 10 years. He said given the high cost of energy, it is critical that the two countries cooperate to address the long-term needs. The two nations can also work together to develop new clean energy technology, he added.

The US will send a high-level trade mission in September to promote sales of American clean energy and environmental technologies.