A deafening silence on the India-United States nuclear agreement during the last four days of the India@60 celebrations was broken by the US on Wednesday, which stated that the 123 agreement must be completed during the term of the present Congress.

"We have changed laws in the US (when we) negotiated the 123 agreement. Both sides have agreed (to it) and it will move ahead," US Ambassador to India David Mulford said in New York on Wednesday, while underlining the importance of the deal.

The deal gives India access to American nuclear fuel and equipment to help meet its soaring energy needs, even though it is not a signatory to the Non-Proliferation Treaty. But the deal has to be approved by the US Congress, the International Atomic Energy Agency and the 45-nation Nuclear Suppliers Group.

"Final steps have to be taken with the IAEA and NSG. A final vote by the US Congress is also required... time is of the essence," Mulford said while addressing the 'India@60: A New Age for Business' conference.

The civil nuclear initiative will help India meet its energy needs, he said, while describing the other areas of Indo-US relations as 'comprehensive'.

Indian leaders present at the function, including External Affairs Minister Pranab Mukherjee and Finance Minister P Chidambaram, have been tightlipped about the deal for the last four days. However, Indian ambassador to the US Ronen Sen made a passing mention about the pact, in the conference organised by the CII and the Ministry of Tourism.

Sen had mentioned that the Indo-US nuclear deal was an example of the strengthening ties between the two nations.

The Left parties, which offer crucial support to the United Progressive Alliance government in New Delhi, have been resisting the implementation of the agreement, claiming that it compromises the country's sovereignty.

Earlier, Mulford described India as "nothing short of a modern miracle" for its attributes that include a large population, parliamentary democracy, rule of law, religious tolerance, great degree of human freedom, a large private sector economy and its peaceful co-existence with the rest of the world.

The American envoy to India added that Indo-US relations were at an all-time high and Washington wanted to see India become a world power.