New Delhi  - Communist partners of India's ruling coalition on Friday asked the government to make it clear by July 7 if it was going ahead to implement its civilian nuclear deal with the United States.

The four left-wing parties led by the Communist Party of India (Marxist) have warned of withdrawing political support if the government approached the International Atomic Energy Agency for India-specific safeguards needed to implement the agreement.

The communist parties, which have 59 members in the Indian parliament, made the demand in a joint letter to India's Foreign Minister Pranab Mukherjee.

"We wish to know definitely whether the government is proceeding to seek the approval of the safeguards agreement by the board of governors of the IAEA," said CPI-M general secretary Prakash Karat, reading from the letter.

"Please let us know the position by July 7," he said.

The communist parties would meet again on July 8 to consider the government's response to their letter, but political analysts said that they could announce the withdrawal only on or after July 10 when Prime Minister Manmohan Singh reaches New Delhi after attending the G8 summit in Japan.

The communists, who provide crucial support to Singh's United Progressive Alliance (UPA) government, have strongly opposed the deal, calling it a sell-out of India's strategic sovereignty and a "cover" to building closer ties with US.

India's main opposition Bharatiya Janata Party has said it would pass a no-confidence motion against the government if the left parties withdrew support. This could lead to a snap election.

The Congress-party-led UPA government is due to end its five-year term in May 2009.

But Singh's government, which is keen to push the deal before the US presidential election in November, has made hectic efforts to avoid early polls and saving the nuclear deal.

The UPA has made steady progress in political parleys to secure the support of the regional Samajwadi (Socialist) Party to offset the loss of support from leftist parties.

Although the SP, which has 39 lawmakers in the Indian Parliament, has not formally announced support for the UPA, an understanding has been reached between the two, political observers said.

If the communists withdraw support, the ruling coalition would be reduced to 226 members in the 543-member Indian Parliament, 46 seats short of the majority figure of 272.

But with backing from SP, the UPA could gain the support of 265 members and securing seven votes for the floor-test would not be problematic as there are a number of fence-sitters and independents, political analysts said.

Meanwhile hectic political activities were on in the Indian capital as the communist parties went into a huddle to work out the timing and modalities of withdrawing support to the UPA government.

The SP also held consultations with Singh and Congress chief Sonia Gandhi.

A delegation of US legislators headed by Democratic Congressman Gary Ackerman was also set to meet Singh on Friday.

Ackerman has said the time was running out for the deal and was hopeful that New Delhi would expedite steps needed to implement the deal.

After reaching a safeguards agreement with the UN, New Delhi has to lobby for an India-specific waiver with the 45-nation Nuclear Suppliers Group and later send the agreement for final ratification by the US Congress.

Under the civilian nuclear agreement, the US has promised to provide India with access to nuclear technology and fuel in exchange for international safeguards on India's civilian nuclear reactors. (dpa)