Chicago, Feb 22 President Barack Obama, who called India an indispensable nation during Prime Minister Dr. Manmohan Singh's state visit, will most likely visit India later this year to further underscore its importance to America, a US official says.

Before that, the upcoming 43-nation Nuclear Security Summit that Obama is hosting in Washington in April, "which we expect Prime Minister Singh will attend, provides an excellent opportunity to highlight this evolving partnership," Assistant Secretary of State Robert O. Blake said on Friday.

The remaining steps in the historic India-US civil nuclear deal are expected to be completed in the next few months, he said, addressing the Chicago Council on Global Affairs "on seizing the opportunities before us in US relations with India".

"The civil nuclear deal turned probably our most significant irritant in bilateral relations into an opportunity for cooperation," he said. "A few more steps are still required, and we expect them to be completed in the next few months."

"This has the potential to lead to billions of dollars worth of opportunities for American companies, and many thousands of jobs as a result of that."

"Indeed, this will be one of the defining relationships this century in American foreign policy," said Blake noting that "In recognition of India's importance," Secretary of State Hillary Clinton visited India last July to launch a Strategic Dialogue with External Affairs Minister S.M. Krishna.

"In a further signal of India's importance to the United States, President Obama hosted Prime Minister Dr. Singh in November for the first state visit of the Obama presidency," he recalled.

"President Obama has further underscored the importance of India to the United States by promising to make a reciprocal visit to India, most likely later this year," he said.

"Both countries believe we now have a unique opportunity to make progress on our broad bilateral agenda," Blake said.