It took Serbian forces just 2-1/2 months to disperse most of Kosovo's 1.8 million ethnic Albanians, who fled into the mountains of Kosovo or over the borders to neighboring regions. Once they start turning back, it could take many months, even years, before they have proper homes to live in again.
Today there are about 860,000 Kosovar Albanian refugees camped or housed outside the Serbian province and a further 500,000 displaced inside Kosovo, many hiding out in the woods, according to the Office of the United Nations High Commissioner for Refugees (UNHCR). The mass return home will be one of the biggest in history.
The UNHCR welcomed Wednesday night's military agreement for Serbian forces to pull out of Kosovo, but it warned refugees not to rush back until it was safe to go home. The UNHCR said it had a team of experts ready to go into Kosovo with a relief convoy as soon as it gets the go-ahead from the KFOR international security force.
The UNHCR's special envoy to the Balkans, Dennis McNamara, says there are enough food supplies, medical aid, and temporary housing to get about half a million refugees back home in the space of three or four months.
First, Mr. McNamara says, the terrain would have to be cleared of mines, unexploded ordnance, and booby traps by experts who had helped secure the land in Bosnia after the 1992-95 war.
Another priority is to get food and other supplies to the thousands of displaced Albanians still trapped inside Kosovo. Relief agencies say there is practically no food left in the province, judging by the poor physical condition of recent arrivals from Kosovo.
There will be no harvest this year, and food stores kept on farms appear to have been depleted, UNHCR press officer Judith Kumin says.
The Rome-based UN World Food Program (WFP) has said it has enough food to feed 1.5 million people for 45 days. It expects to have an additional 12,000 tons of provisions by the end of the month, but it is appealing for more supplies from member countries.
About 50 percent of homes and other buildings in the province have been destroyed, McNamara says, in what has been described as "scorched-earth tactics" by Serbian forces. Bridges and roads into the province have been bombed by both NATO and Serbian forces.
The UNHCR wants to help monitor the Kosovar Albanians' return. Many had been forced to surrender their personal papers, passports, and vehicle registration documents to Serbian forces on leaving Kosovo and would need to be issued with new papers for their return. "The registration of refugees is key, and it is not clear yet who will control the return," McNamara says. "A form of documentation is crucial."
Yugoslavia has said it has the right to check refugees reentering Kosovo under a peace plan agreed in Belgrade last week, but it was unclear whether this meant they would merely have observer status or whether they would actually have the powers to turn refugees back.
UNHCR spokesman Kris Janovski says if the Serbs were vested with the power to stop people, it would defeat the whole purpose of NATO's 2-1/2-month bombing campaign. "They've tried to destroy the whole place and erase the people's identities. The Yugoslav authorities cannot be trusted. They may have a symbolic presence at the border, but should not be allowed to have any say on who crosses over," he says.
Some refugees would probably return "spontaneously" in cars and tractors soon after the peace agreement, McNamara says. But most would probably need to be transported back in specially organized buses accompanied by relief agencies with logistical aid, including plastic sheeting, blankets, food, and medical supplies.
McNamara says there would be no transit camps. Refugees would be taken back to their homes - even if these had been burned down - and helped to set up tents there until they could build new homes or move back in the old ones.
While many Albanians and Serbs say they will probably never live side by side again, UNHCR officials fear another humanitarian crisis: that the return of hundreds of thousands of Albanians could in turn spark another mass movement of ethnic Serbs in the opposition direction - to elsewhere in Serbia.
Before the conflict, there were some 200,000 Serbs in Kosovo, UNHCR officials say. About half have left since the outset of the conflict, and there are fears the rest will also take to their heels once the Kosovar Albanians come back.
"We don't know how many Serbs are in Kosovo, it's important that the return of the refugees does not create a new refugee exodus. That's a challenge for NATO; that's a challenge for us all," McNamara says.