At 2.09 a.m. on Saturday, Ahmad Subhan, who lives near an air base in the Pakistan military garrison city of Rawalpindi, heard the first explosion that rattled the windows of his house - and took South Asia to the brink of war.

Yet, the danger of nuclear war remains "relatively small" between India and Pakistan, according to Mr Clary. "So long as there is not major ground combat along the border, the dangers of nuclear use remain relatively small and manageable," he said.