The United Nations faces an enormous challenge in establishing an interim administration in Kosovo - a challenge of a kind it has never really faced before.

But the limits within which it will have to work in large part reflect the distrust felt by many over the UN's performance in the past in the Balkans. The task will therefore be a tough one, but also a crucial opportunity for the UN to demonstrate that it can function effectively in the region.

In Bosnia the UN came in for sharp criticism over its failure to act firmly or swiftly enough to prevent bloodshed.

Distrust of the UN meant that when the Dayton accords were signed the UN was largely written out of the script.

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In Kosovo, the UN has been put back in the picture, partly on the insistence of the Russians and the Chinese, partly because the Yugoslav Government wanted a UN element to justify ending the war, and partly because of Nato's sensitivities about criticism of the alliance's decision to launch air strikes without Security Council backing.

As in Bosnia, the military force in Kosovo is not under UN control - although it has the authority of a Security Council resolution behind it, the peacekeepers do not wear UN blue helmets. Instead they are a distinct coalition of Nato and Russian troops.

However UNMIK, the UN's mission in Kosovo, has daunting responsibilities on the civil side.

It must do its best to oversee the return of the refugees, the provision of food and shelter, the rebuilding of Kosovo's ruined economy, the establishment of new systems of law and order and the setting-up of democratic institutions to which it might eventually hand over power.

Building from the ground up

The Swedish UN envoy to the Balkans, Carl Bildt, who was High Representative in Bosnia, says there has been no challenge facing the UN like this before.

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He says the organisation will learn a lot from its experiences in Bosnia, but adds that whilst there it was a question of dealing with existing structures, in Kosovo the UN will have to work from "ground zero" in building entirely new institutions.

Questions have already been asked about how the UN will go about creating a new police force or developing new courts and new laws without infringing the territorial integrity of Yugoslavia which is meant to be respected under the Security Council Resolution.

The UN will have to give consideration to matters such as collecting taxes or issuing stamps and passports. Although the politics of this could be sensitive, Carl Bildt says most inhabitants of Pristina are less concerned about political theory and more about the pressing problem of getting some form of garbage collection going again.

A mesh of institutions

To help it in its major role the UN will have the assistance of the European Union which has special responsibility for economic reconstruction and the Organisation for Security and Co-operation in Europe which will take the lead in developing democratic institutions.

Whilst a UN Special Representative will be in overall charge of all these areas, he or she will not have authority over the military commander of K-For. Instead the two are being seen as equals. The word is that the civil and military sides are now working together well.

But with so many different organisations and delicate relationships in play, the past experience of the Balkans indicates that the potential for rivalry between different institutions and individuals is ever present.