The under secretary of state for political affairs and the chief US negotiator of the US-India civilian nuclear agreement, Nicholas Burns, is most frustrated with the stalled bilateral civilian nuclear cooperative accord, known as the 123 Agreement. But that is apparently just the tip of the iceberg.

Burns and other senior administration officials had hoped that the negotiations over the 123 Agreement last month in New Delhi would resolve any pending issues so it could be sent up to Congress for review.

After that, the administration could go to bat for India at the Nuclear Suppliers Group plenary meeting in Cape Town, South Africa, this week.

But the officials are incensed that India played hardball at the negotiations, with New Delhi continuing to express concern over certain provisions of the enabling legislation approved by Congress and signed into law by President Bush in December.

Consequently, these sources told rediff.com that 'the list of differences between the two sides' seemed to be getting longer than before, at a time the US was hoping the 123 Agreement could be completed and the US-India civilian nuclear deal presented at the NSG plenary.

Now, because of New Delhi's stalling, as Washington perceives it, the agreement will not be presented at the NSG meeting in Cape Town.

The usually unflappable Burns last month expressed frustration with New Delhi for continuing to balk on completing the 123 Agreement that is essential for Congress to review before it ultimately votes on the enabling legislation to consummate the deal.

Burns was buttonholed by reporters on March 29, just after he testified before the Senate Foreign Relations Committee on the growing crisis with Iran. He was then asked to comment on the US-India 123 Agreement negotiations in New Delhi.

He said the administration has been hopeful of making progress but admitted that while some progress was made, the administration did not think that was enough.

Richard Boucher, assistant secretary of state for South and Central Asian Affairs, also expressed frustration after visiting New Delhi during the first week of April as an observer to the SAARC summit.

He lamented the dissipation of the momentum over the deal and said it was now India's responsibility to get it going again.

In an interview, Boucher said, "The United States is really carrying through all its commitments and is ready to conclude an agreement on the basis that the President and Prime Minister Manmohan Singh agreed upon. At this point, the ball is in India's court."

He said the administration was 'anxious to make progress', and hoped there could be talks with Indian officials to push things on.

Sources said that the departments of Commerce and Energy, where the secretaries of both agencies -- Carlos Gutierrez and Sam Bodman, both back from visits to India -- have called on India to complete the 123 Agreement so that American business and industry that had invested much in lobbying Congress to approve enabling legislation as the first phase of the agreement, could get be a player in India's civilian nuclear power and technology market.

According to the sources, the US negotiators had done all of the negotiating they could 'and they do not have any more negotiating room'.