Under Secretary of State for Political Affairs Nicholas Burns will be arriving in India on Thursday from Berlin to continue negotiations between India and the United States on the proposed agreement to operationalise the civilian nuclear deal.

With 90 per cent progress already reported on the talks on '123 Agreement,' Burns will be in New Delhi for three days to hold talks with Foreign Secretary Shiv Shankar Menon to sort out the remaining differences.

Washington has said that both countries are 'well on the way' to conclude the pact and that it did not believe any of the remaining differences were 'insurmountable.'

The two sides will seek to wind up the year-long negotiations ahead of the meeting between Prime Minister Manmohan Singh and US President George W Bush in Germany next week on the sidelines of the G-8 Summit.

"He will (Burns) be arriving in India on Thursday. And this will be to continue the discussion on the 123 agreement that is an important component of implementing the overall US-India civilian nuclear deal," Deputy Spokesman of the State Department Tom Casey said in Washington.

He said the deal was beneficial to both the countries and it will strengthen nonproliferation regimes.

"Certainly, we believe that such a deal is in the interests of both countries. We want to see this move forward," Casey said at his regular briefing.

"We have talked about the civil nuclear arrangement for a number of months now. But it is something that we believe is beneficial to both nations. It represents a new level of cooperation between our countries. And we also think it represents a strengthening of nonproliferation regimes.     

"It certainly is something that has been endorsed by the International Atomic Energy Agency as something they think will be helpful and beneficial and will provide greater surety to the world," he added.

The deputy spokesman parried a question on the kind of details that still needed to be 'hashed out' saying that this is an area he would like to leave it to the negotiators of the two sides.

"Obviously, they have been talking about this for a while. There are some differences that remain. But we are looking forward to being able to work those out. We certainly do not think any of them are insurmountable," he said.

"As we have said in the past, we need to make sure that this arrangement does conform with the relevant US legislation that this is under, so there are limits to the kind of flexibility we can have. But the Indian government understands that. And I think we are well on our way toward an agreement.

"I am not trying to predict anything will come out of this particular trip, but we are making progress. And we look forward to eventually concluding the deal," Casey said.

The key negotiators of the two sides will aim at resolving differences on aspects like reprocessing right and continuity of civil nuclear cooperation if India were to conduct an atomic test in future.

The meeting between Menon and Burns was expected to take place last week but was postponed as the US had sought some technical clarifications on a draft text presented by India, sources said.

The clarifications were provided by India at a two-day expert-level meeting in London from May 21 after which the two sides reported 'further progress' towards finalising the mutually-agreed text of the agreement.