Ahead of the meeting of the United Progressive Alliance-Left Committee on nuclear issues on Tuesday, the Communist Party of India-Marxist on Monday made it clear that it would not allow the government to proceed on the Indo-US nuclear deal.

"The 123 agreement is anchored in Hyde Act and we don't want the government to proceed on it with such provisions," CPM politburo member Sitaram Yechury told reporters in New Delhi.

At Tuesday's meeting, he said, the Left parties will see "what kind of discussions the government has had with the International Atomic Energy Agency."

As part of implementation of the Indo-US nuclear deal, India concluded negotiations with the IAEA on the Safeguards Agreement in February but it could not be signed because of stiff opposition from the Left parties.

The Left parties, which provide crucial outside support to the government, had stressed that the agreement should be signed only after they examine the pact and give a go-ahead.

Tuesday's meeting has been called to deliberate on whether India should go ahead with signing the agreement.

"We will consider what the government will report to us on its talks with the IAEA. On that basis, we will take the issue forward," a senior Left leader had said earlier when asked about the stand that the four supporting parties are going to adopt at the upcoming meeting.

After the last round of UPA-Left meeting on March 17, the Left parties and the government have been exchanging notes on related issues, but no details are available. Though Left leaders have refused to divulge details about these exchanges, informed sources said these related to several political and technical matters like assurance on uninterrupted fuel supplies.

The Left has been opposing the deal on the grounds that the conditions laid down by the Hyde Act would impinge on India pursuing an independent foreign policy and make it "subservient" to US strategic interests worldwide.

Indicating a shift in its stand, External Affairs Minister Pranab Mukherjee recently said the government would seek "the sense of the House" on the stalled deal before it goes to US Congress for ratification. However, Left sources said the government already knows "the sense of opposition to the nuclear deal expressed in both Houses of Parliament. The government has no majority on the issue. What more do they need?"

The safeguards agreement with the IAEA and a waiver from the 45-member Nuclear Suppliers' Group, enabling India to participate in nuclear commerce, are the two pre-requisites to operationalise the Indo-US civil nuclear deal.