India, which has not signed the global non-proliferation pact, is anxious to reassure Washington it can be trusted, especially after the discovery of an international nuclear black market linked to Abdul Qadeer Khan, the father of rival Pakistan's atomic weapons programme.

"We see no reason for non-proliferation concerns to be a barrier to high-technology trade and commerce with our country," Singh said on Tuesday, adding India's safeguards met the best global standards.

Washington imposed restrictions on sharing nuclear technology after India and Pakistan conducted tit-for-tat test explosions in 1998 -- and as head of Delhi's atomic agency at the time, Chidambaram was banned from the United States.

But sanctions were dropped after Washington sought South Asia's help in its war on terrorism following the Sept. 11, 2001, attacks on the United States.

Last September, it lifted decades-old curbs on equipment for India's nuclear and space programmes and recently pledged to help its old Cold War foe in its quest to become a major economic and diplomatic power.

"The diplomatic challenge before India and the United States is no longer about making the case for nuclear energy development," Indian strategic affairs analyst C. Raja Mohan wrote in Wednesday's The Indian Express. "It is about finding practical ways to resolve differences on non-proliferation."

India is Asia's fourth-largest economy and its largest energy consumer after China and Japan. India's gross domestic product grew 6.9 percent in the year ended March.

Nuclear energy accounts for only three percent of India's power production, but it aims to raise nuclear output to 25 percent of total power generation by 2050 to help offset massive imports of oil and gas.

"Nuclear energy is an imperative for India," Uday Bhaskar, of the Institute of Defence Studies and Analyses told Reuters.

"The Americans have recognised India's nuclear restraint and responsibility. This is in sharp contrast to the A.Q. Khan experience in Pakistan."

Pakistan is the focus of a probe into a nuclear black market linked to Khan.

But irritants between India and the United States remain.

In September, the United States imposed sanctions on two Indian scientists it accused of co-operating with Iran, which Washington says is secretly developing its own nuclear weapons.