The US embassy in Belgrade was in flames last night after a mob of Serbian protesters peeled away from a rally against Kosovan independence and broke into the empty building, tore the Stars and Stripes from the flagpole and set rooms alight.
Police took nearly half an hour to appear at the scene as young men, many in balaclavas, tore open the boarded-up building, throwing chairs and papers onto the street and chanting nationalist slogans.
One protester climbed up to the first floor of the building, ripped the US flag from its pole and briefly put a Serbian flag in its place.
Some protesters jumped up and down on the embassy balcony, holding up a Serbian flag as the crowd below of about 1,000 people cheered them on, shouting "Serbia, Serbia".
A 200-strong force of riot police did eventually appear, firing tear gas and arresting some of the protesters.
Earlier, more than 150,000 Serbs had gathered in central Belgrade at a government-organised rally against the independence of Kosovo. They filled the large square in front of parliament, the eight lane-boulevard before it and a nearby park. The largely peaceful "Kosovo is Serbia" rally drew large numbers from all over the country with the help of free buses and trains.
Speakers recalled the angry nationalist rhetoric of the later 1990s by calling for confrontation with the US and the EU because of their support for an independent Kosovo.
"Kosovo belongs to Serbia," the normally reserved conservative Prime Minister, Vojislav Kostunica, shouted into a microphone. "It has been so for time immemorial and it will be forever. No force, no threats or promises can change that," he added as the crowd roared back, in a clear reference to his government's defiance of closer ties with the EU.
The crowd emotionally cheered Mr Kostunica's address and waved Serbian flags; they also carried banners saying "Kosovo is Serbia", "Stop the US terror". A red and black Albanian flag was set on fire, with policemen looking away with complete indifference.
State television switched between scenes of the rioting and the choral singing of the church service.
Shops in Belgrade were closed and private security forces closely guarded international banks and foreign companies. There were widespread fears of a repetition of the violence that swept the city when Kosovo declared independence on Sunday. Concerns were mounting after last night's rally that a new crackdown against political opponents and a ban on all criticism of the government would follow the nationalist upsurge.
Many say that the atmosphere ominously resembles the dark days of the Milosevic era. The rhetoric at the rally and in the street recalled the outpouring of hate towards the West. American films and TV series have been withdrawn from the state broadcaster, and dissenters are being publicly slandered or even threatened. All who differ from the official line have been harassed by so-called "patriots", while international shopping centres have been stoned with the tacit approval of the authorities.