FOCUS: WAR IN EUROPE: The fresh and terrible fears for those that remain

t was the eerie silence, the empty valley that was so strange. Serbia's ethnic cleansing machine cranked up a gear yesterday, forcing thousands more terrified Kosovars out of their homes and into northern Albania.

But for the first time in 40 days, at the notorious Kosovo-Macedonia border post at Blace, where the customary array of aid workers, doctors, soldiers and journalists awaited the expected flood of terrified humanity, not a single person came.

On the wide sweep of the Lepenec River valley, where once tens of thousands of Kosovar Albanians were trapped, and where every day for weeks upwards of 5,000 people waited to be processed and taken to the camps, there was only the sound of birdsong. And up through the man-made gorge that sweeps down to the border from the Serbian side we could see that the highway from Pristina, the now infamous pipeline down which 240,000 refugees have come, was totally deserted.

"It is the strangest thing we have seen since this began," said Paula Ghedini of the UNHCR. "Something very sinister is happening up there. We have good intelligence that tens of thousands of people should be on that road today, that they should be arriving every hour, and for 24 hours nobody has appeared."

That intelligence consists of accounts from other refugees that a new offensive was being carried out by Serbian forces in dozens of villages in the western region of Kosovo. In the last three days some 20,000 people have been cleared from their homes, and should have been on the road south. Instead, they have simply disappeared.

"They are either living in the mountains and the woods or they are being held in other places," she said. "There are very large numbers involved here and somebody is keeping them back. The Serbs are undoubtedly up to something new and perhaps controlling the flow of people for purposes that we don't yet understand."

In the Kosovo refugee tragedy, anecdote and rumour leak out from a sealed and hidden landscape, where brutal forces are busily at work and people are dying. Inside a superbly equipped field hospital built by the German army, the traumatised figure of nine-year-old Albiana Aliu was living proof of the murder and attempted murder of children. Two nights before, a German naval surgeon removed a high-velocity bullet from her side, fired by a Serbian police officer at a distance of 100 yards.

Beside her lay her cousin, Refice Aliu, aged 14. In her case a bullet had gone completely through her flesh. Both children had been carried by their fathers for six days and nights, bleeding heavily and largely unconscious, through forests and mountain valleys until they got on a train.

But there was worse. Back in the forest, Albiana's brother, Ljavdim Aliu, aged 11, was now buried under a few feet of soil and leaves, with a simple wooden stake to mark his grave. He was shot by the same men. He lived only a few hours and died in his mother's arms.

This is the account of Albiana's uncle and father of Refice, a 47-year- old farmer called Muharem Aliu from the village of Dobratina, near Podujevo: "They rounded up our entire village, about 1,500 people in all, and they fire-bombed our houses and told us to march down the road.

"But then I looked around and I saw them raising their rifles and they began firing. My daughter and my niece fell to the ground. A few feet away I saw the bullet hitting Ljavdim on the neck. Others were also hit. They just fired and fired. People fell all around us and we ran for our lives.

"When the little boy died we could not carry him. We prayed for him and we buried him. His mother did not want to leave him. We had to force her away. We hope that we can go back and find him and bury him properly. We will try."

There it was. A hundred witnesses. Two living victims. The bullet itself as evidence. But who were the men who fired the shot? Who can identify them behind their strange uniforms and the face-masks many of them wear? That is the problem that will some day face the war crimes investigators when they try to balance the books for history.

The largest single group escaping into Albania came from the Istok area, 3,000 people ordered out of villages and organised into a tractor convoy. On the way young men were hauled out and taken away by Serbian forces to an unknown fate, while others were beaten and robbed.

"They stopped all the tractors and made the young men get out. They went past, pointing - you, you, you. We left at least 60 young men there," said Drahim Berisha, a cut over his eyebrow and bloodstains on his sweatshirt testifying to the beating he took.

Worst of all, the family left Drahim's 90-year-old father Rexhep Berisha behind, since the masked paramilitaries who forced the family out of their Mercedes did not notice the old man. They demanded money: Drahim paid DM500 (pounds 170), but the men ordered the Berishas to climb on to a tractor and leave immediately. "I had to leave my father," Drahim said. "I felt very sad but what could I do, I have three children to protect."

A second group left the town of Djakovica after Serbian forces swept through a neighbourhood, searching house-to-house for young men and then setting the buildings ablaze.

Adrian, who would not give his last name, said perhaps 200 young men were arrested in his area and that he escaped only by saying he was an invalid. "Some of no more than 14 or 15 years old were separated from their families - the Serbs were calling them KLA," he said.

By 3pm yesterday, 5,500 people had crossed the Morini border post in Albania. This means that since the Serbs began cleansing Kosovo on 24 March, they have expelled 407,460 people into Albania, another 197,870 into Macedonia and 61,700 to Montenegro. In six weeks, President Slobodan Milosevic has forced almost 700,000 people out of their homes.

Meanwhile, somewhere out in the mountains of Kosovo last night, those missing thousands that are perplexing Paula Ghedina and the UNHCR officials in Macedonia are being held back for some reason - and they, too, will have more stories to tell.