The enforced deportations are bringing the Serbs closer to their goal of ethnically cleansing Kosovo of its 2 million Albanian inhabitants.
The Serb police were herding Albanians from the capital, Pristina, on to the trains "like sardines", the UN High Commissioner for Refugees said.
A spokeswoman, Judith Kumin, said three trains with 5,000 aboard had arrived at the border yesterday and two more were reportedly on their way. The first three arrived the day before.
The refugees told of being dragged out of their houses in Pristina and herded into a crowded quarter of the city on a hillside. "When the trains pulled in, people were pushed down the hill and crammed on to the train. Two old people died in the crush," Ms Kumin said.
Many of the refugees, especially the elderly, collapsed when they got off the trains after being forced to walk almost two miles between the final railway station in Kosovo and the Macedonian frontier post, at Blace.
Kris Janowski, a UNHCR spokesman, said the scenes of columns of people staggering along the railway line reminded him "of the darkest days at the end of World War Two, with refugees streaming in all directions - men women and children and the elderly, clutching a few precious possessions.
"Everyone interviewed told similar stories of masked men in uniforms knocking on doors and telling people to leave or be killed," Mr Janowski said.
Survivors who reached Macedonia told horrifying accounts of the emptying of Pristina of its mostly Albanian population of more than 250,000. "I counted about 15 dead in my street," said one woman. "Near the mosque I saw the body of a 17-year-old boy; I know his father. There is no one left in Pristina now."
Nearly all the refugees are women and children. They say their menfolk are either hiding out in the hills of Kosovo, or have been captured and killed by the Serbs.
"We saw them take about 50 or 60 men," said Sanije Morina. "We saw nothing but heard guns firing. We don't know what happened."
The refugee accounts dovetail with reports of mass graves containing hundreds of bodies near the central town of Orahovac.
The number of Albanians pouring out of Kosovo is so great that the worry now is that there will soon be none left in Kosovo for Nato to help.
Partly in answer to such fears, Nato yesterday said it would shell Serbian artillery positions near Malisevo, central Kosovo. The Serbs are pounding one of the last Albanian centres of resistance there.
The alliance believes about 50,000 Kosovars - many of them refugees from other parts of Kosovo - are trapped in a triangle of territory, defended by poorly armed fighters from the Kosovo Liberation Army.
With no sign that Nato's air campaign has checked the Serb offensive, Serbia celebrated a second propaganda coup yesterday, parading the Kosovo Albanian leader Ibrahim Rugova on Serbian television.
The public display of an exultant Slobodan Milosevic and a dazed Kosovo leader, on the same day as TV showed three captured US soldiers, crowned a day of triumph for the Serbs on their ninth day at war with the Western alliance.
Earlier reports had suggested Mr Rugova was dead, murdered in a systematic purge of intellectuals, politicians and writers. But on Serbian television Mr Rugova was quoted as saying that he was "under the protection of the Serbian police". He made no known mention of the awful fate of his countrymen.
A bland Serbian television announcement said Mr Rugova and President Milosevic had "discussed the problems in Kosovo. They came to a joint stand on a mutual commitment to a political process."
Although the Kosovo leader could be seen smiling glassily, Western officials who watched the soundless clip said Mr Rugova was obviously there under under duress. "It was an eerie sight," said one diplomat based in Macedonia.
In Washington, the Defense Secretary, William Cohen, said the US would "stay the course" in the conflict with Serbia, in spite of a series of setbacks. "We are making progress in our goal to damage and diminish," the forces of President Milosevic, he said.
Mr Cohen was in Norfolk naval station, Virginia, where President Bill Clinton last night made a speech to the families of those involved in the Yugoslav campaign. On Wednesday President Clinton was quoted as telling a delegation of Albanians living in the US: "We cannot lose this. We have to win this." The White House has warned that Nato air strikes on Yugoslavia may go on for weeks.
Nato yesterday reiterated that it had no intention of engaging in a land war with Serbia, saying this would require 200,000 troop. "No one is seriously proposing the planning of an invasion force," an alliance diplomat said. "There's still confidence that Milosevic will crack under continued pounding from the air." The Nato secretary-general, Javier Solana, said: "The only plan to send in ground troops at this moment is to guarantee a peace agreement. The allies are not contemplating the deployment of ground troops to fight their way in."
As the scale of the humanitarian catastrophe worsens, the UNHCR said it may set up an air bridge to Albania, along the same lines as the Sarajevo airlift of 1992-95. A British jet is already in Albania, which will shuttle between Tirana and UN stores in Denmark.Reuse content