US-India Political Action Committee said the agreement will help build a strategic partnership between two of the greatest democracies in the world that could well redefine the 21st century.

"US and India have achieved what everyone thought was impossible when President George W Bush and Prime Minister Manmohan Singh [Images] announced their plan for a civil nuclear agreement in July 2005," USINPAC Chairman Sanjay Puri said in a statement.

"Exactly two years later, the two nations have not only reached an agreement, but created a lifelong partnership between two nations that are committed to democratic principles and the idea of energy independence," he said.

"It is a historic milestone in the US-India relations," Puri said while noting the role played by Indian-Americans in clinching of the deal by working with US and Indian officials.

Universally regarded as one of the most important pacts of the 21st century, the US-India Civil Nuclear Agreement lays the foundation stone for India's energy self-reliance and opens avenues for American businesses to invest in the country's booming economy, Puri said.

In the aftermath of the deal, he stressed the need for a sustained, long-term multi-sector dialogue between the two nations.