Ahead of a high-level meeting between India and the US on the civil nuclear deal, Prime Minister Manmohan Singh [Images]  spoke to US President George W Bush on Wednesday in an apparent bid to give a political push to negotiations stuck due to differences over some issues.

They 'spoke about the forthcoming discussions between the National Security Advisers of both countries', prime minister's media advisor Sanjaya Baru said.

National Security Adviser M K Narayanan will hold talks with his US counterpart Stephen Hadley in Washington on July 16 to break the logjam on the negotiations for the 123 Agreement, the operational pact for the civil nuclear deal.

The negotiations have failed to yield any breakthrough due to differences on issues like reprocessing of spent nuclear fuel and India's right to conduct a nuclear test in the future.

In view of the persisting differences, negotiators of the two sides have said a political push would be required to break the logjam.

During the telephonic conversation, Dr Singh and Bush said they looked forward to 'continuing their own discussions at their next meeting', which is expected in September when the prime minister travels to the US for the UN General Assembly session.