India's communist parties say they will stop supporting the government if it pushes through a nuclear deal with the United States.
Prakash Karat, the head of the Communist Party of India, said the communists will not be there to help the government conclude the deal. He told reporters in New Delhi Thursday that the communists' objections should be considered before the agreement is approved.
The leftists say the deal undermines India's independent foreign policy.
Karat's group is the largest of the four communist parties that support Indian Prime Minister Manmohan Singh's ruling coalition. The coalition could collapse without their support.
The pact would allow India to import U.S. nuclear fuel and reactors even though it has tested nuclear weapons and has not signed the Nuclear Non-Proliferation Treaty. But the deal would require India's compliance with safeguards agreed on by the International Atomic Energy Agency and the Nuclear Suppliers Group