By Sanjoy Majumder
BBC News, Delhi
India's main communist party has warned the government against implementing a controversial civilian nuclear agreement with the United States.
There have been isolated protests against the nuclear deal
The communists provide critical support to the Congress-led Indian government.
The stand-off is the worst crisis to hit the government since it came to power in 2004, prompting speculation that it could lead to early elections.
Under the deal, India will get civilian nuclear technology and fuel despite not signing a non-proliferation treaty.
After a two-day meeting, India's main communist party said it did not want the crisis to affect the government, but it added that was contingent on the government not going ahead with the civilian nuclear agreement.
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.
But the communists have made it clear that they do not want these discussions to take place.
The stand-off is into its second week and with no sign of either side backing down, India could well face early elections although neither party is keen on having 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.