ISLAMABAD/NEW DELHI ¨C 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 ¡ª 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.

The critical eight-hour window also saw Indian missile barrages on three major Pakistani air bases and other facilities, including Nur Khan, which is ringed by civilian homes like Subhan¡¯s, and just a 20-minute drive to the capital, Islamabad.

After the initial blast, Subhan and his wife grabbed their three children and ran out of their home. ¡°We were just figuring out what had happened when there was another explosion,¡± said the retired government employee, who remembered the precise time of the strike because he was just about to make a call.

This account of Saturday¡¯s events ¡ª which began with the looming specter of a full-blown war and ended with an evening ceasefire announcement by U.S. President Donald Trump ¡ª is based on interviews with 14 people, including U.S., Indian and Pakistani officials, as well as Reuters¡¯ review of public statements from the three capitals.

They described the rapid escalation of hostilities as well as behind-the-scenes diplomacy involving the U.S., India and Pakistan, and underscore the key role played by Washington in brokering peace.

The attack on Nur Khan air base saw at least two missile strikes as well as drone attacks, according to Subhan and two Pakistani security officials, who like some of the people interviewed, spoke on condition of anonymity.

The barrage took out two roofs and hit the hangar of a refueling plane, which was airborne at the time, according to one of the officials, who visited the base the next day.

A senior Indian military officer, however, told reporters on Sunday that an operations command center at Nur Khan had been hit.

¡°The attack on Nur Khan ... close to our capital, that left us with no option but to retaliate,¡± said Pakistan Foreign Minister Ishaq Dar.

Nur Khan is just over a mile (1.6 kilometers) from the military-run body responsible for Pakistan¡¯s nuclear planning.

So, an attack on the facility may have been perceived as more dangerous than India intended ¡ª and the two sides should not conclude that it is possible to have a conflict without it going nuclear, said Christopher Clary, an associate professor at...