Now Indian Prime Minister Manmohan Singh has a tough choice to make - override his own scientific establishment or suffer a serious loss of face when President George W. Bush visits his country in early March.

"The government is debating this very seriously," said foreign policy expert C. Raja Mohan. "Some big decisions have to be taken."

The deal, agreed in principle when Singh visited Washington last July, would offer India access to nuclear technology and reactors -- at a stroke removing much of the stigma India attracted when it conducted nuclear tests in 1974 and 1998.

In return, New Delhi offered to separate its civilian and military nuclear programmes - and place the civilian part under international supervision.

But that is where the deal could come unstuck.

The US administration, under pressure from a hesitant Congress, wants to see more of India's programme under international supervision than New Delhi is offering.

At the heart of the debate is a prototype Fast Breeder Programme, which would process plutonium from spent fuel from India's existing Heavy Water reactors.

The chief of India's Department of Atomic Energy Anil Kakodkar went public with his objections in a newspaper interview published in full on Wednesday. Placing the Fast Breeder under international supervision would "shackle" his scientists and leave the country dependent on imported uranium, he said.

"Both from the point of view of maintaining long-term energy security and for maintaining the 'minimum credible deterrent', the Fast Breeder Programme just cannot be put on the civilian list," he said. "This is not in our strategic interest."

Nonsense say the deal's supporters. DAE, long a secretive and isolationist organisation, is simply scared of opening up, ignoring long-term strategic goals for its own narrow interests.

"There is a very strong turf battle going on," said Dr Harsh V. Pant, a lecturer in defence studies at King's College, London. "The scientific establishment wants to defend its turf."

Singh, already under fire from his Communist allies over the deal, has promised to address parliament later this month about the deal. Promising to defend India's national interest, he vowed there was "no question of bending" to American demands.