Assault on the Serbs: Nato draws a line and tells Serbs to pull back or die

NATO DREW a line across Yugoslavia yesterday and threatened death from the skies if Serb troops and police did not pull back behind it. The 44th parallel, 60 miles south of Belgrade, entered military history as Nato escalated air attacks in the first offensive against a sovereign state in its 50-year existence. It said Serb tanks and troops moving south of the line towards Kosovo would be pounded from the air.

Last night Kosovar sources said Nato had attacked a Yugoslav army column near Malisevo, central Kosovo, knocking out four tanks.

The announcement, from Nato headquarters in Brussels, came as evidence grew that Serb forces are committing "genocide" in Kosovo.

"We are confronting a regime ... intent on genocide," said George Robertson, Secretary of State for Defence. adding that the Serb paramilitary chief known as Arkan, infamous for acts of terror against civilians in Bosnia, may be helping to conduct a scorched earth policy.

There was more evidence yesterday of Serbs "ethnically cleansing" huge parts of Kosovo, marching tens of thousands of women and children to the border in the snow.

Nato officials said Europe may be about to confront its worst humanitarian catastrophe since the Second World War, equalling or exceeding the carnage in Bosnia. "We estimate that the number of people displaced from their homes in Kosovo has gone over the half-million mark and that number is increasing at a rapid rate," a Nato spokesman said.

The UN refugee agency (UNHCR) in Geneva said as many as 16,000 Kosovars had fled to Albania in the past 48 hours, and that tens of thousands had gone to Bosnia and Montenegro, a part of Yugoslavia under a pro-Western government. Italy also braced itself for an influx of refugees. Last night several hundred landed in the southern region of Puglia. "They were driven out of their homes at gunpoint," a UNHCR spokesman said.

Aid agencies said the refugees forced into neighbouring Albania were stripped of their identification cards and car number plates on the frontier to ensure they never return.

In Washington, Madeleine Albright, Secretary of State, said she had heard "terrible reports about men being separated from women and children, then being taken off and executed".

Defying claims that by riling the Serbs Nato may be worsening the plight of the Kosovars, Ms Albright said the alliance would intensify attacks on Serb targets. Britain said it was sending four more Harrier jets to join forces flying against the Serbs, bringing the total to 12.

General Sir Charles Guthrie, Chief of the Defence Staff, said that the attacks on Yugoslavia "will not diminish. Indeed, they will increase".

As a pattern emerges of "ethnic cleansing" on a big scale in Kosovo, fears are growing that the fragile governments in neighbouring Albania, Macedonia and Montenegro may collapse under the strain of the tide of refugees.