Congress spokesman Manish Tiwari said the 123 agreement has not been changed which was a "victory" for India.

"Indian nuclear programme continues to be intact. It is a victory for India.

"It opens nuclear trade with the rest of the world. The future generations will not have to face any electricity shortage," he said.

"Today we celebrate the festival of Vijayadashami, today good won over evil. It's a big day for India as the American President has finally signed the Indo-US nuclear deal."

Warning that the nuclear accord will have "serious" consequences for India, Raja said its signing can be seen as a result of "mutual desperation".

"While Manmohan Singh (PM) wants to show some achievement at the fag end of his tenure, the Americans are desperate to help the military-industrial establishment at a time when US is passing through a mega financial crisis," the CPI leader said.

Maintaining that American nuclear companies were waiting for the massive Indian market to open up for their revival, he said "they see the Congress-led UPA government helping them in this.

"Nobody knows what the economic cost of this deal will be for India. It will simply be huge...it will have very serious consequences for India and its future," Raja said.

He also said that it is finally the prerogative of the US to ensure uninterrupted fuel supplies for India. "We will have to see how far the Indian government has yielded to the US," he added.

External Affairs Minister Pranab Mukherjee and US Secretary of State Condoleezza Rice will formally sign the overall bilateral nuclear cooperation accord early Saturday morning.