The United Progressive Alliance and the Left are expected to firm up a mechanism on Thursday to address the concerns of the allies which have insisted on government awaiting its findings before operationalising the Indo-US nuclear deal.

While setting up the mechanism may lower temperature in the stand-off, the Left parties are insisting that government should not pursue the safeguards agreement with the International Atomic Energy Agency for the time being and wanted a commitment on this count.

Modalities of the committee were discussed at a meeting attended by Prime Minister Manmohan Singh [Images], Congress President Sonia Gandhi [Images], External Affairs Minister Pranab Mukherjee and Defence Minister A K Antony.

The four Left parties also met to chalk out their joint strategy ahead of their meeting with UPA leaders on the issue.

"The government's decision may be formally declared to us tomorrow," Communist Party of India-Marxist leader Sitaram Yechury said, maintaining that the government should not proceed with operationalising the agreement till this committee comes out with its findings.

Asked whether there should be a timeframe for the committee to submit its findings, Yechury said, "Yes, there has to be a timeframe without specifying it. The nuclear issue is expected to come up for debate in Parliament on September 5-6. A decision will be taken by the business advisory committee."