Miss Mihailova insists that Balkan borders stay unchanged

But Bulgarian Foreign Minister Nadezhda Mihailova warned those calling for a halt to the air campaign, the region needed a complete solution to the conflict, including an end to President Slobodan Milosevic's policy of ethnic cleansing.

Speaking at a UK Ministry of Defence news conference in London, Miss Mihailova said it wasn't possible to be neutral over Kosovo - one was, she said, either in favour or against the Yugoslav policy of intolerance.

During her remarks, Miss Mihailova repeated Bulgaria's belief that all national borders in the Balkans must remain unchanged. 'We want no more Balkanisation of the Balkans', she said.

'Refugee bomb'

Compared to other countries in the region, Bulgaria has received few refugees from Kosovo. The United Nations refugee Agency, UNHCR, says around 2,500 people have crossed into Bulgaria.

But Miss Mihailova said her country was very worried about the effects of the refugee influx on the economic and political life in Albania and the Former Yugoslav Republic of Macedonia.

She said President Milosevic was deploying a 'refugee bomb' in an act of real aggression against his neighbours.

Earlier in the bombing campaign, Nato was embarrassed when a stray missile hit the Bulgarian capital, Sofia. There were angry demonstrations in Sofia after the incident; but shortly after, the Bulgarian government later approved the use of national air space for Nato fighters and bombers.

The British Prime Minister, Tony Blair, is due to visit Sofia later this month. Mr Blair is due to meet his Bulgarian counterpart, Ivan Kostov, as well as President Petur Stoyanov.