Click here for a map of refugee movements

Hundreds of refugees crossed into Albania late on Friday via the main border post from Kosovo - where the flow was abruptly stopped at about 0300 (0100 GMT) on Wednesday.

The refugees - some 1,500 of them - were all reported to be inhabitants of one village, near the Kosovo capital Pristina.

Duncan Kennedy reports from Kukes in Albania

Officials from the Organisation for Security and Co-operation in Europe (OSCE) said it appeared to be an isolated event, and it remained unclear if the border was now open.

The villagers said Serb police entered their community earlier on Friday, and told them to leave, according to OSCE officials.

Refugees still missing

Queues of refugees have also amassed on the Macedonian border which was deserted on Thursday.

A long line of cars can be seen stretching back several hundred metres at the crossing point.

Paul Wood: Refugees are gathering on the Macedonia border again

But there is also confusion there over whether the border is open or closed.

Nato and international aid agencies are still trying to establish the fate of up to 200,000 Kosovo Albanians who have been unable to cross over the border into neighbouring countries.

Nato spokesman Jamie Shea said that between 150,000 and 200,000 refugees could be living without shelter in the woods and mountain slopes of Kosovo.

With the help of the UN refugee agency, the UNHCR, the alliance is trying to work out what had happened to a group of "car people" turned away from the province's border with Albania earlier this week.

Queue disappears

The Macedonian border has seen strange and unpredictable movements of refugees in recent days.

At one point, a 30 kilometre queue of vehicles simply disappeared as the Yugoslav security forces told refugees to return to their homes.

Belgrade then stated that the border was open, but until now the roads have been deserted.

Paul Wood reports from Skopje: Mrs Ogata received assurances from the Macedonian Government

The UN High Commissioner for Refugees, Sadako Ogata, on a trip to Macedonia, says the government there has promised her it will not close the border to refugees as it did earlier this week.

However, several Kosovar women could be seen on Friday waiting in the no-man's land after the Yugoslav border posts - raising doubts as to whether the Macedonian side is open.

Burnt out cars

The handful of refugees who have made it across the borders in the last two days have spoken of lines of abandoned and burned-out vehicles along the border roads inside Kosovo.

Fergal Keane reports on life behind the wire fence of a refugee camp in Macedonia

Nato spokesman Jamie Shea said the UNHCR and the Red Cross had still not been allowed access to investigate the situation.

Nato says it has ferried more than 1,300 tons of aid to Macedonia

UNHCR spokeswoman Maki Shinohara added: "People who have made it into Albania all say the same story, they say there are a lot of tractors, trailers and cars abandoned on the road inside Kosovo.

"There is no way for us to verify what has happened on the other side of the border, but the reports we are hearing is that some people were forcefully turned back.

"We don't know what is going on, and that is very worrying."

Ogata's camp tour

The UNHCR estimates that some 510,500 people have now actually left the province for neighbouring countries.

During her trip to Macedonia on Friday, Ms Ogata toured one of the largest refugee camps to have sprung up in the past week.

The UNHCR chief has made clear her disapproval of the Macedonian policy carried out in recent days of deporting refugees instead of sending them to the new camps set up by Nato.

She said the UNHCR would shortly take over the running of the relief camps established with Nato's help.