While K-For troops may be pouring into Kosovo after the end of 78 days of Nato air strikes against Yugoslavia, the mammoth effort needed to get the refugees back to what may remain of their homes is only just beginning.

The United Nations' refugee agency, the UNHCR, has urged caution over how quickly the hundreds of thousands of displaced people can return to normal life.

Daniel Endres, head of the UNHCR emergency team in Albania, said international bodies would be trying to stop refugees flooding back until security was guaranteed.

"I don't think we can move a large number of refugees into Kosovo very quickly because of the great level of destruction," said Mr Endres.

"The first condition is security and dignity for the returnees, and that needs to be insured by a credible force."

Click here to see a map of refugee movements

The entire effort to return refugees hinges on the state of the province after the Serb withdrawal - and the shape of any political settlement which follows.

But the most crucial factor preventing the refugees returning home is the presence of land mines.

At least one refugee died and four were injured when a group of 3,000 ran into a mined area as they crossed back into the province from Macedonia.

British troops who led the entry into Kosovo through the Kacanik pass between the province and Macedonia immediately encountered mined stretches of road and bridges.

There are also fears of booby traps in the homes and villages of refugees - and K-For leaders predict it could take up to four months to deal with all the mines.

The US State Dept has pledged $1.6m to a six-team mine clearance operation, drawn from specialists already working in Bosnia and Croatia.

Poisoned water

There is also growing concern that mass graves discovered near to villages may poison the water supply, leaving many areas uninhabitable for months.

Troops: Forces in before refugees home

The World Health Organisation found similar cases of poisoning in Bosnia after war crimes victims were buried in hastily dug graves.

Furthermore, according to latest UNHCR estimates, up to half of the homes in Kosovo may have been destroyed and up to 70% damaged since 24 March.

Wells are said to be polluted, crops have either failed or were never planted in time and Nato has bombed much of the province's electricity supply.

The reconstruction of Kosovo will cost a lot more than the $70m needed to keep refugees in camps for another three months - an international reconstruction deal is said to be in the pipeline.

Priorities

The current proposed repatriation operation is divided into four phases:

• Preparation for return
• Resumption of humanitarian operations in Kosovo
• Promoting repatriation
• Sustainable reintegration

Kris Janowski of the UNHCR said: "We don't have a handle on how bad the destruction is in Kosovo. We will go in as quickly as the security will allow and look at the situation."

The fact-finding teams are currently assessing critical basics for sustaining life - water supplies and sanitation - and are making a detailed inventory of the damage to homes in the province.

But the teams are already taking emergency supplies to the thousands of refugees internally displaced within Kosovo, hiding in the mountains and forests. Around 20,000 such people have already been found.

Once phase one is complete, humanitarian organisations will lay groundwork for the major return and reintegration of refugees to follow.

Infrastructure repairs will initially focus on homes and communications such as roads and bridges.

Echoes of the past

While the UNHCR believes large numbers will be prepared to return quickly if Belgrade keeps to its word, the region's other major movement of refugees is yet to be resolved.

Current estimates suggest that up to one million people are still displaced following the war in Bosnia following the collapse of Yugoslavia - officially described as Internally Displaced Persons (IDPs).

"The big difference between Bosnia and Kosovo is that after the Dayton peace agreement in 1995 the return of refugees was essentially hindered by the fact that people were returning to areas where they were in the ethnic minority," said Mr Janowski.

"The position in Kosovo is different as the returning Kosovo Albanian refugees are the majority.

"The problem will be in ensuring that the Serb communities do not believe that they are now in a hostile environment."

Communities returning to Bosnia after the Dayton peace agreement have found it difficult to settle following a war which saw former neighbours become ethnically divided enemies.

But agencies working in the Balkans fear that the effects of the destruction will take a far greater psychological toll on the Kosovo refugees.

"In a traumatised population people don't think rationally," said Sue Prosser, a psychotherapist with Medicins sans Frontieres.

"They think that their homes will still be there, may be in need of a little bit of decorating.

"They won't think that their home may have been booby-trapped, that there is no electricity, no infrastructure, or maybe no home at all."