The Left parties on Monday said they were now discussing the timing of withdrawing support to the UPA government as they feel it was determined to go ahead with the Indo-US nuclear deal, an indication of which is the Prime Minister's trip to G-8.

The four Left parties are in discussions among themselves on when to withdraw support to the Congress-led coalition and a decision is likely to be taken at their meeting here on Friday, Left sources said.

They said that Prime Minister Manmohan Singh [Images] had earlier stated that he would not attend the G-8 summit in Japan [Images] until he got a clearance on the nuclear deal.

Now it looks like he is going to attend the summit, starting on July seven, which makes it clear that the government will go to the Board of Governors of the IAEA to get the India-specific safeguards agreement approved, the sources said.

The Prime Minister's offer to come to Parliament before operationalising the Indo-US nuclear deal has not cut much ice among the outside supporters as they feel it would be a "fait accompli" as this would be done only after all the processes to operationalise the deal were gone through.

The processes include clearances from the IAEA and getting a waiver from the 45-nation Nuclear Suppliers Group and an endorsement from the US Congress, they said, wondering what was the use of coming to Parliament once the processes is over.

With the CPI(M) politburo deciding to withdraw support the moment the government takes the next step to go to the IAEA, the CPI, RSP and Forward Bloc are likely to meet separately during the week before finalising their joint strategy on Friday.