India and the United States will hold another round of talks to narrow down differences on a proposed agreement that will operationalise the civilian nuclear deal when Foreign Secretary Shivshankar Menon travels to Washington later this month.

Menon will undertake a two-day visit from April 30 during which he will hold talks with US Under Secretary Nicholas Burns on the 123 agreement amid indications that Washington was 'frustrated' at the speed of the negotiations.

The meeting between Menon and Burns will be held ten days after senior officials from the two sides met in the South African city of Cape Town. Indian officials had said that 'some progress' was made during the discussions, which spanned over five days.

Indian officials, however, maintained that some differences remained and further parleys were required to sort them out.

The contentious issues in the proposed agreement relate to New Delhi's right over reprocessing of spent nuclear fuel and the fallout if India were to conduct an atomic test in future.

India, while noting its declared policy of unilateral moratorium on nuclear testing, refuses to make it legally binding by including a clause in the 123 Agreement. New Delhi insists that civil nuclear cooperation should not be affected if India were to conduct a nuclear test and should be treated at par with other nuclear weapon countries in this regard.