It was not diplomatic sweet nothings that President George W Bush [Images] whispered to Prime Minister Manmohan Singh [Images] at the airport tarmac upon his arrival in New Delhi [Images] on Wednesday evening, but even as flashbulbs popped the two leaders were negotiating the nuclear deal.

Ahead of Bush's arrival, US Secretary of State Condoleeza Rice telephoned the prime minister to complain that the Indian negotiators were making 'impossible demands' and pressed for greater flexibility by them. Dr Singh stood firm in backing his team.

As millions watched on television, Bush put his arm around Dr Singh; the two men engaged in an animated chat for several minutes with their principal aides standing nearby. The focus was the unresolved differences between the negotiators.

The US President told Dr Singh, who had made a departure from protocol to receive him, that he never engaged in negotiations.

However, Bush asserted, 'I want this deal,' according to the details of the tough, tortuous and down-to-the-wire negotiations that preceded the nuclear agreement a day later.

• Complete coverage: President Bush visits India

The deal nearly did not happen but for this last-minute intervention by the US leader, sources involved in the talks said on Saturday.

With this clear directive from their President, the American negotiators engaged in negotiations with their Indian counterparts till about 2 am on Wednesday night-Thursday morning.

Hours later Bush and Dr Singh announced the landmark deal.

During her telephone call to the prime minister, Dr Rice had insisted that New Delhi should accept permanent safeguards of its nuclear facilities to which Dr Singh responded by stating that he would have no problem with that as long as the US assured India [Images] perpetual fuel supplies.

The prime minister made it clear to her that he could not negotiate outside his statement to Parliament that only 65 per cent of India's nuclear facilities would come under international safeguards.