The US legislature has to give mandatory approval to the landmark nuclear agreement but lawmakers are reportedly sceptical as India has refused to sign the Nuclear Non-Proliferation Treaty (NPT) and has developed nuclear weapons on its own.

"If this particular agreement does not go through, there is no doubt there will be, in terms of the expectation that has been created, in terms of the enthusiasm that has been created, there will be some falling back," Saran said when fielding questions on the deal at a Washington forum.

Saran, the top civil servant in the Indian foreign ministry, said inevitably the public focus of the envisioned strategic partnership between the two nations had been on the nuclear deal even though bilateral relations covered many key areas.

"If this does not go through, it does not mean that everything else will fall by the wayside but at the same time we should also recognise that for good reason or bad, there is intense focus on this particular agreement," he said.

"Therefore whether we like it or not, this has become very symbolic of what we want to do with India-US relations," he said.

The nuclear deal was clinched on March 2 by US President George W. Bush and Indian Prime Minister Manmohan Singh

It gives energy-starved India access to long-denied civilian nuclear technology in return for placing a majority of its nuclear reactors under international inspection.