India's ruling alliance is meeting its communist allies after the latter asked the government to put on hold a nuclear deal with US for six months.
There have been isolated protests against the nuclear deal
The communists provide key support to the Congress-led government. The stand-off is the worst to hit the government since it came to power.
US officials say the civilian nuclear deal needs to be completed in time.
Under the deal, India will get civilian nuclear technology and fuel despite not signing a non-proliferation treaty.
The government is due to begin key negotiations with the International Atomic Energy Agency (IAEA) and the Nuclear Suppliers Group for the deal to be carried through.
'Resolve through dialogue'
But the communists have made it clear that they do not want these discussions to take place prompting speculation that the stand-off could lead to early elections.
A senior leader of the main Communist Party of India (Marxist), Prakash Karat, told a public meeting on Tuesday that the government should put on hold the implementation of the nuclear agreement for six months.
"Let parliament debate the nuclear deal first, and the government should consider widespread opinion among scientists and intellectuals which has been against the deal," he said.
"We don't want a political crisis. But in a democracy, the opinion of people is what counts, and we represent the third biggest party in the government. The stand-off should be resolved through dialogue."
Meanwhile, the US Ambassador to India David Mulford told a meeting in Delhi that "time is of the essence" in the implementation of the deal.
Mr Mulford said that the two countries had signed the agreement and "now we must take the last steps [to implement the deal]".
The meeting between the Congress-led ruling alliance and the communists comes at a time when a group of senior Indian officials are attending a meeting of the IAEA.
The chief of India's Atomic Energy Commission Anil Kakodkar told the meeting that nuclear power was an "inevitable option".
If the month-long stand-off between the government and its communist allies shows no signs of abating, India could well face early elections although neither party is keen on them.
The nuclear deal is at the centre of a strategic shift in ties between India and the United States and is seen by the government as a major achievement.
But it is being opposed by both the communists and the main opposition BJP who say it compromises India's sovereignty.