The first explosions were distant, sounding like a dull thud, followed by a faint reverberation. Then, minutes later, came a blast that echoed across the walls of the multi-storey estate where I was standing, and the sky lit up with anti-aircraft fire.
With those explosions, NATO began the first attack on a sovereign European state in its 50-year history. When NATO prepared to bomb Serbia in February and last October, alarms were not heard in Pristina. No one took the threats seriously.
This time few doubted that NATO meant business. "The sirens are for real. This is not a test," said Zoran Andjelkovic, who as president of Kosovo's interim executive council is the top Serb official in the province.
In spite of the sirens, which started at 1.30 p.m. and lasted for about 15 minutes, there was no rush to take cover. Many people were already leaving their offices. Others had stayed away.
In a largely Serb-populated housing estate called Ulpiana, Pristina's only purpose-built underground shelter was firmly padlocked. "Someone must have a key," said a middle-aged Serb woman disinterestedly, as she carried her shopping home.
Other residents were hostile. "Journalists? Where from? Britain? I'm going to call the police," hissed another woman. A heavy-set man bellowed at us to leave.
At Gracanica, a Serb community, patrons of a cafe resisted all the efforts of our Serb interpreter to answer questions. As the first wave of attacks rolled in towards the combined Serb civilian and military airfield, about four miles west of Pristina, the only living things in the street were dogs that greeted the explosions with furious fits of barking.
What sounded like Yugoslav anti-aircraft fire followed a few seconds later. And then the power was cut and the city fell into darkness. The flickering light of candles soon appeared in high-rise apartment windows. Five minutes later the sky lit up again with a firework display of red flashes.
Even before the city went dark, some Serb families switched off their lights, in line with emergency instructions on television. Air-raid sirens sounded intermittently.
Albanians on their balconies watched in excitement mixed with foreboding. "This is the only thing that could be done," said Ismail, a former civil servant who was sacked eight years ago when all Albanians were dismissed from government posts.
"This is the beginning of the path to a solution."
"I am very happy," Dardane Arifaj, a young pharmacist, added. "At last the international community has started to do something concrete for us."