The symbol of Kosovo: an eagle with two faces – each looking a different way

As Kosovo prepared for its independence and the biggest party in its history today – 80 tons of fireworks have been imported and that's just for the official celebration – the European Union announced that it will provide a 2,000-strong police and justice mission to the fledgling nation. It will include 700 police as well as judges, prosecutors and other legal experts, and will replace United Nations administrators over a 120-day period.

The announcement from Brussels drew immediate condemnation from the Serbian government in Belgrade. Slobodan Samardzic, Serbia's minister for Kosovo, called the decision "shameful". The mission "officially recognises the independence of Kosovo," he said, "which remains an inalienable part of Serbia".

When independence comes this afternoon, Albanians in the divided city northern city of Mitrovica will be partying as hard as anyone. The southern part of the city is festooned with Albanian flags, the roads strung with bannerswhich declare: "Gezuar Pavaresia" – or "happy independence".

Yesterday, the festive mood had already taken hold; 14-year-old Mervan Gashi strode proudly with a double-eagle flag draped over his shoulders. "We've waited so long for this day," said his friend Ilir Becaj, 13. "We're feeling great, and we're not worried about security because KFor" – the Nato force garrisoned across Kosovo since the end of its civil war – "will protect us."

"It's going to be the biggest party in the history of the world," declared Hajdari Hajdar, an elderly man in a beret and long black coat. "We've waited centuries for this. We are only in this miserable condition because of the Serbs, if it wasn't for them we'd be like the United States. For hundreds of years we've sent all our wealth to Belgrade. Not any more!"

But on the far side of the shabby bridge that both joins and divides this gritty industrial city, the mood was very different. Since the war ended in 1999, Mitrovica has been the most explosive corner of the Balkans, the flashpoint where paramilitaries enforced a strict ethnic split. Serbians live on the north bank of the River Ibar and the suburbs that climb the steep hills overlooking the town, and Albanian Kosovars are confined to suburbs south of the bridge. The communities are almost within spitting distance, but for eight years they have kept to themselves.

Violence erupted here in March 2004 when two dozen people were killed and hundreds of houses destroyed unedr the noses of Nato troops. That showed how easily one spark can start a conflagration. On Thursday night a bomb went off in the Serbian quarter, in a house next to the offices of the EU mission. There were no injuries.

The Serbian paramilitaries, who years ago forced Albanians out of their homes and across the bridge, hung out in the Dolce Vita coffee bar, strategically located within sight of the bridge. Yesterday this smoky den was crammed with short-haired, muscled young men, but the mood was laconic.

"For the moment things are quiet," said Alexander Veselinovich, 36, an electrical engineer born in the town. "But people are a little bit afraid because they have had negative experiences with these types of celebrations and they don't know what to expect. We accept UNMIK police who patrol here" – the UN force – "but we will never accept Pristina's institutions." Nor, he swears, will they accept the new policemen who are on their way from Brussels.

As usual in the Balkans, each side blames the other for violence. But what is indisputable is that fear or dislike of solitude have induced thousands of Serbians from the enclaves dotted across Kosovo to flee to the haven of northern Mitrovica. They have set up little shops in prefabricated kiosks that line the main road, and their desperation has made them difficult neighbours. "They have lost everything," Veselinovich points out, "and now they are trying to grab everything." And they are often particularly hostile to the Albanians. In last month's presidential elections, 75 per cent of Mitrovica's Serbians voted for the ultra-nationalist Tomislav Nikolic. They are in no mood for conciliation which all gives Mitrovica a special air of volatility.

Despite all the fine words, ethnic integration has never been a realistic goal in Kosovo. What distinguishes this from earlier Balkan flashpoints is that the Serbians were perceived as, and often behaved like, arrogant colonialists. "The Kosovo Serbs don't speak Albanian," the political scientist Slobodan Markovic pointed out in Belgrade this week, "so there is no possibility of integration." Solid in their conviction of superiority and their ancient right to this land, the Serbians expected the Albanian Muslim majority to kowtow to their greater power and wealth. And for generations they did so.

That imbalance was gradually righted in the years after Tito granted the province broad autonomy in 1974. But then Slobodan Milosevic threw the gears into reverse in 1989 when he annulled autonomy and putting Kosovo once again under the Belgrade thumb.

Now, at last, the Albanian Kosovars are officially in the driving seat. Today they get their own flag, their own national anthem; a constitution is under construction; and a new, lightly armed Kosovo Protection Force will be controlled by the Kosovo government. Embassies are expected to open in the US, Japan and in most of the EU, including Britain.

Northern Mitrovica will remain fiercely hostile towards Pristina, and umbilically tied to Belgrade. As for Kosovo's other Serbian enclaves, home to 60 per cent of the Serbian population, even if they are not threatened with violence by their newly powerful Albanian neighbours, a sad, steady stream of tractors piled with possessions can be expected to set off on the trek to northern Mitrovica. It's the logic of the Balkans, and nothing the outside world can do seems able to change it.