The Left parties on Friday stepped up their demand for a threadbare discussion in Parliament on the Indo-US nuclear deal and a statement from the government reflecting the 'sense of the House' on the vital issue.

The nuclear deal was discussed at a meeting of the four Left parties in New Delhi, a day after the Communist Party of India (Marxist) joined hands with Bharatiya Janata Party to demand a resolution in Parliament on the matter.

"All parties will participate in discussions in Parliament. You cannot say that CPI(M) is with BJP or BJP is with CPI(M). The issue is about national security," Revolutionary Socialist Party leader Abani Roy said after the hour-long meeting.

The meeting, he said, was called to workout a joint strategy to be adopted in the floor of the House on various issues, including the nuclear deal. There was no official briefing after the meeting.

Communist Party of India leader D Raja told PTI that the government should address the concerns of the Left parties and Parliament in its 'collective wisdom' must spell out the parameters of the deal to counter pressures and changes sought to be brought about.

The CPI had on Thursday said that it would not go with the BJP 'in any way' on the deal after Prime Minister Manmohan Singh [Images] conveyed to it that such a move would spell the downfall of the United Progressive Alliance government.