The UN refugee agency says the border at Blace was closed on Wednesday - the day after Macedonia accepted another 8,400 Kosovo Albanian refugees.

The Former Yugoslav Republic of Macedonia has been struggling to cope with the arrival of more than 200,000 refugees since March.

Western donors have announced plans to donate $252m of aid to deal with the emergency.

The BBC's Rageh Omaar: "Border post now completely deserted"

Donor nations and international financial agencies hope to top up the aid to $400m later in the year.

General Wesley Clark, Nato's Supreme Commander in Europe, says refugees may not be able to return home until next year.

Border closed

Macedonia, which has closed its borders on other occasions, says the refugee burden is threatening its economy and its own ethnic mix.

Correspondent Paul Wood in Macedonia: "Troops turned back refugees"

And Macedonian state television reports that the authorities have decided only to accept as many new refugees into the country as leave on airlifts to third countries.

Less than 30,000 refugees have been moved out of Macedonia since Nato began Operation Allied Force on 24 March.

The UN refugee agency (UNHCR) says that on 4 May, 8,400 new refugees arrived and 1,130 left to third countries.

UNHCR spokeswoman Paula Ghedini said that at 1500GMT on Wednesday the Blace border was closed.

She said: "We were given no notice of it and we think many people were either not allowed in or pushed back into no man's land. We are extremely concerned about the situation."

International aid

Police closed the border

The $252m aid package is made up of donations from Japan, the United States and European Union nations, and smaller grants from a host of others.

It includes a "stand-by" credit line of $32.6m from the International Monetary Fund, and two separate credits from the World Bank, worth $60 in total.

Macedonian Finance Minister Boris Stojmenov welcomed the pledges as "timely and swift".

Bleak future

General Clark has acknowledged it may be next spring before ethnic Albanians forced out of Kosovo can go home to anything like a normal life.

He said: "Crops have not been planted so the food supply's not there. Homes have been destroyed, roofs ripped off, houses, apartments blown up and whole villages apparently just destroyed.

"So even when they're allowed to go home, life won't be normal for a while. I think that we have to look very much ahead, past the summer, into the autumn, the winter and even the next spring."