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.

As dawn broke, the heaviest fighting in decades between nuclear-armed India and Pakistan reached a crescendo, after nearly three weeks of escalating tensions.

Fighter jets and missiles crisscrossed the skies of one of the world's most populated regions. Pakistani officials said they would convene an emergency meeting of their top nuclear decision-making body.