US Under Secretary of State for political affairs William Burns, who was scheduled to arrive in New Delhi on Monday ahead of a crucial meeting of the Nuclear Suppliers Group (NSG), has postponed his visit at the last minute.

“Burns has postponed his visit to India. He is likely to come to India later this month,” an official source said IANS.

“But no dates have been fixed yet,” the source added.

Burns, a former envoy to Russia, is busy dealing with the crisis arising out of Russia's intervention in Georgia, the source said.

Burns, however, may come to India after the 45-nation NSG's meeting in Vienna Aug 21-22 to consider an exemption for New Delhi from the existing rules of global civil nuclear commerce.

With some sceptics among nuclear suppliers still unconvinced about the merits of the India-US civil nuclear deal, there is a strong likelihood of a second meeting of the NSG which could happen early September before the US Congress considers an approval for the 123 civil nuclear agreement in September.

Foreign Secretary Shivshankar Menon has been in constant touch with Burns over diplomatic efforts required to get the backing of the NSG countries for the nuclear deal.

Every country matters in the NSG as the grouping that controls the flow of global nuclear technology and fuel operates by consensus.