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.

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.

India and Pakistan have been pushed a step closer to war after a gun massacre of tourists on April 22, their most serious confrontation in decades.