India and the US on Monday began talks on an agreement to operationalise the civil nuclear deal amidst New Delhi's firm insistence that it will accept no deviation from the understanding reached between the two sides last year.

Officials of the two sides met in New Delhi for talks on the 123 Agreement during which they will seek to iron out differences over various elements in the Henry Hyde Act.

India has alleged that the Hyde Act, passed by the US Congress in December last year to allow civil nuclear trade with India, "significantly deviates" from the understanding of July 18, 2005, and March 2006, which was unacceptable to it.

New Delhi's concerns particularly relate to elements relating to reprocessing of spent fuel, end-use monitoring, fuel assurances, future nuclear testing and fissile material control.

New Delhi has already conveyed its concerns to Washington and handed over a draft text of the agreement suggesting the clauses it wants to be incorporated.

At the two-day talks, the Indian side is led by Joint Secretary in External Affairs Ministry Gayatri Kumar while the American delegation is headed by Richard Stratford, director of Nuclear Division in the State Department.

Officials of the Department of Atomic Energy and S Jayshankar, Indian ambassador to Singapore, are also participating in the talks. Jayshankar was Kumar's predecessor and had been involved in the parleys earlier.