The Left parties on Saturday declined to comment on a newspaper report that Prime Minister Manmohan Singh [Images] has dared them to withdraw support to his government due to differences over the India-United States civil nuclear deal.

When contacted, Communist Party of India-Marxist politburo member Sitaram Yechury and Communist Party of India national secretary D Raja declined immediate comment, saying they could raise the matter in Parliament.

Calcutta-based daily The Telegraph on Saturday quoted Dr Singh as saying, 'I told them that it is not possible to renegotiate the deal. It is an honourable deal, the Cabinet has approved it. We cannot go back on it. I told them to do whatever they want to do, if they want to withdraw support, so be it.'

The report said the prime minister's virtual challenge to the Left parties, whose 64 members in the Lok Sabha provide a crucial make or break support to the UPA government, comes in the context of strong statements made by CPM leader Prakash Karat and CPI A B Bardhan. The Left leaders had warned that the government may have to pay a 'heavy price' if it went ahead with the nuclear deal with the US.

The paper quoted the prime minister as saying he was not angry but anguished at the harsh tone and tenor of the reaction and made it clear that the UPA-Left relationship could not be a one-sided affair.

'I don't get angry, I don't want to use harsh words. They are our colleagues and we have to work with them. But they also have to learn to work with us,' the paper quoted Dr Singh as saying.

Singh, who had spoken to the Left leaders after their rejection of the nuclear deal, said there was no immediate response by the Left leaders to what he had told them.

They haven't thought it through, the report quoted him as saying.

The prime minister felt that the Left had a flawed understanding not just of the 123 Agreement but also of India's intrinsic strength and its enhanced status in the world.

Singh said the deal was an honourable one which enlarged India's development options particularly in regard to energy security and environmental protection and doesn't in any way affect our ability to pursue our nuclear weapons programme.

'We have not surrendered an iota of our freedom in this regard, not an iota of our sovereignty,' the prime minister said.

Quoting the government's principal scientific adviser and former chairman of the Atomic Energy Commission R Chidambaram, the prime minister said all three conditions -- that there would be no effect on our strategic programme, no deceleration in our three-stage nuclear power programme and no effect on advanced Research and Development programmes -- have been met.

To a question on why the Left was objecting to the deal, Dr Singh told the daily, 'I don't know -- they seem to have a problem with the US.'

The prime minister said he wanted India's relations to improve with all the powers -- the US, Russia [Images], EU, France [Images] and particularly with China -- and that the government was doing that.

'We have had a breakthrough with China, a historic agreement where we have defined the principles that will outline the border agreement.'

To the Left's fears that the 123 Agreement would draw India further into a strategic alliance with the US rendering it an American satellite, the prime minister said 'How can we ever become anyone's satellite?'

'Yes, we live in an increasingly interdependent world but the challenge before us is to forge new linkages, widen our strategic options and, at the same time, guard against the negative side of the process of globalisation.'

'Look at Vietnam, look at China -- out of fear of dealing with the US, we cannot become a frog in the well.'

'India, with a billion people and with such a diversity of languages and cultures and religions, with its functional democracy and respect for rule of law, is a unique country.'

'We are a role model for the world,' he said.

Dr Singh felt that the Left was 'underestimating the intrinsic strength of India, of India's capacity to defend its national interests.'