Indian communists sought to forge a consensus on Wednesday over whether to end support to Prime Minister Manmohan Singh's coalition government over a controversial nuclear deal with the United States.

The issue is the main item on the agenda of the central committee of the Communist Party of India (Marxist), or CPI(M), which began a two-day meeting to chart its strategy over its opposition to the civilian nuclear energy deal.

The stand of the left parties -- who together have 60 MPs in the lower house of parliament -- has triggered Singh's worst political crisis since he came to power in 2004, threatening to topple his government and lead to early elections.

Asked if the left parties would force elections ahead of their schedule in 2009, senior communist leader Biman Bose said: That is what we are here trying to discuss.

Other leaders said the ball was in the court of the ruling Congress party, and it was for the government to decide whether to give in to the communists and put the nuclear deal on hold or pursue it and risk early elections.

The left has asked the government not to pursue negotiations with the International Atomic Energy Agency (IAEA) to conclude a key safeguards agreement until all its concerns are addressed.

It has warned the government of serious consequences if it went ahead.

The deal will allow India to buy nuclear fuel and reactors from the U.S. -- and eventually other countries -- even though it has not signed the Non-Proliferation Treaty and has tested nuclear weapons.

But the communists, as well as the opposition Hindu nationalists, say it compromises India's sovereignty, with the left parties also saying it imposes American hegemony.

While the communists and the ruling Congress party are trying to resolve the crisis, they have made little progress, with Congress indicating it was not willing to relent.

Some CPI(M) leaders said the central committee was divided over whether it should end support and force early elections or find a face-saving way out of the confrontation.

Analysts say some communists, particularly from their stronghold state of West Bengal, are not keen to face voters because of anger among farmers there over the state government's move to take farmland for industries.

We don't want elections immediately but the ball is in the government's court, said a senior leader, who spoke to Reuters on condition of anonymity.

What is more important? India's international image or the wishes of the Indian people? the leader asked, referring to criticism that going back on the pact would hurt New Delhi's international standing.