The Congress and the Left parties on Friday made moves to defuse the stand-off over the Indo-US nuclear deal, with the announcement that they would open a dialogue on the issue next week.

Cutting short her visit to South Africa, Congress president Sonia Gandhi [Images] returned to Delhi and immediately presided over a meeting of the party core group to discuss the issue with Prime Minister Manmohan Singh [Images] and other top party leaders.

"We will talk to them (the Left) next week after discussing among ourselves," Sonia's political secretary Ahmed Patel told reporters after the meeting.

The Communist Party of India-Marxist, the principal party in the Left grouping, showed further signs of softening its attitude by dismissing all talk of any crisis facing the Dr Singh government.

"I don't see it as a crisis. Where was it and where has it gone? What we are saying is don't proceed without evaluation," politburo member Sitaram Yechury told reporters.

Prior to the core group meeting, External Affairs Minister Pranab Mukherjee briefed Sonia reportedly on the possible options to resolve the impasse triggered by the Left demand that the government should not go ahead with the deal.

The Left sources said there was no immediate word from the government to them on talks.

Congress was likely to hold another meeting of the core group in the next couple of days before holding discussions with the Left.

There was, however, no likelihood of any Congress Working Committee meeting on the issue.

The setting up of a mechanism to sort out the differences on the nuclear deal is expected to be discussed in the meeting between Sonia and the Left leaders next week.

The CPI-M has already expressed its readiness for a mechanism to evaluate the implications of the Hyde Act on the condition that the government should not proceed further with operationalising the deal.

Earlier in the day, Yechury said the government should only press the 'pause' button and not the 'stop' or the 'eject' button.

He said the CPI-M Politburo's position stood reiterated by the Central Committee.

Till the implications of the Hyde Act were properly evaluated, the government should not proceed further with operationalising the deal, he said, seeking a structured debate in Parliament.