Air defence units were placed on heightened alert, and people queued petrol and food supplies.

But they continued to go to work and send their children to school as normal.

Media outlets that had survived a clampdown by the authorities gave citizens instructions on what to do in the event of strikes.

Ben Brown reports on the "panic and terror" in Pristina

The Defence Ministry ordered people to close their apartments during air raid alerts and proceed to air shelters calmly, where smoking and alcohol would be forbidden.

Kosovo Albanians continue to flee the province

While some in Belgrade did not believe that Nato would carry out its threat, others were not so sanguine.

Milena, a pensioner, said: "I was up all night waiting for them to strike. I sat and dozed off occasionally but I couldn't go to bed.

"It's the uncertainty. Psychologically, it's hard. You don't know when it will fall."

Evacuation

Jacky Rowland reports on the "grim inevitability" in Kosovo

State-run Belgrade radio played solemn choral music which, according to some locals, had not been heard since former Yugoslav Communist leader Josip Broz Tito died in 1980.

A steady flow of ambassadors and their families continued to leave from the capital, but staff at the Chinese and Russian embassies have reportedly all remained.

Russia and China are both against the Nato air strikes.

Nick Thorpe: "A state of the imminent threat of war is in force"

The BBC's correspondent Nick Thorpe said that in Belgrade, a big gap has opened up in the daily routines of those who are critical of the government.

"They can no longer listen to B92 Radio, until now the most important independent media in Yugoslavia which was closed down in a pre-dawn raid by police," he said.

The station however has succeeded to defy the shutdown by continuing to broadcast on the Net and via satellite.

Kosovo

In the province of Kosovo itself, there were unconfirmed reports that Serb security forces had shelled Kosovo Albanian villages on Wednesday.

The Kosovo Information Centre (KIC) in Pristina said villages were shelled in the regions of Podujevo and Vucitrn in the north, Kacanik in the south and Decane in the west.