She said the government was particularly concerned about the fate of those remaining inside the province.

Many people were being forcibly prevented from leaving the war-torn province, at a time when the violence perpetrated by the Serbs against the ethnic Albanians was increasing, she told a UK Ministry of Defence briefing.

"Since the borders were closed on 6 April, and the long queue of refugees waiting at the border forcibly turned back, we have been greatly concerned about the situation of the displaced people inside Kosovo," she said.

Claire Short: Only small numbers leaving now

Added to the 540,000 Kosovo refugees who have left the province, the number of internally displaced people meant the overwhelming majority of Kosovo's original 1.8 million population had been forced from their homes, she said.

(Click here for map of latest refugee movements)

Ms Short said the situation of the displaced people within Kosovo was especially alarming in light of new revelations about gross human rights abuses within the province.

'Bosnian war criminals hired by Milosevic'

Arkan denied charges of being a war criminal

In addition to previous allegations about rape camps, UK Defence Secretary George Robertson told the same briefing that two indicted war criminals from the Bosnian conflict were involved in the Serb oppression of Kosovo.

General Radko Mladic and paramilitary leader Arkan have been recruited by the Belgrade leadership to command and supply units responsible for "massacring and raping" thousands of ethnic Albanians, he said.

George Robertson: "Brutal thug releasing hardened criminals to terrorize the people of Kosovo"

Mr Robertson said Arkan had been indicted by the war crimes tribunal in The Hague for the massacre of 250 men taken from a hospital in the town of Vukovar in 1991.

In the first revelation of details from the previously-secret indictments, the defence secretary added that General Mladic was also accused of involvement in the slaughter of up to 10,000 men in the Bosnian enclaves of Srebrenica.

"This is the kind of man that Milosevic hires when he wants a job done," Mr Robertson said.

Duncan Kennedy in Kukes: "This is one of the poorest countries in the world, but with one of the richest senses of kindness"

"If brutal killers like these two are at work, it is no wonder that so many Kosovans have fled their homes in terror."

He also said that Arkan was recruiting convicted criminals from Serbia's jails to join a Tiger force in Kosovo, while General Mladic was actively commanding another detachment of Yugoslav forces in the province.