The retreating forces in the south of the country were given a 24-hour extension after Nato acknowledged they were being held up by traffic congestion.

A Nato spokesman said the alliance was convinced the Yugoslavs were making a "sincere effort" to comply with the requirements for a pullout and that the situation would be viewed with a "liberal attitude".

K-For Commander, Lieutenant-General Sir Mike Jackson, said the Serbs had clearly complied with the peace agreement, and that any stragglers would be easily rounded up and moved north.

Serb forces have four more days to complete their withdrawal from the rest of Kosovo.

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At a Nato briefing Lt Col Robin Clifford revealed more than 26,000 VJ and MUP personnel out of an estimated 41,000 in Kosovo had left the province.

He said that the retreating troops had taken 110 tanks, 210 armoured personnel carriers and 151 items of artillery or mortar pieces with them.

Thousands of Serb civilians are fleeing

Part of the congestion which led to the informal deadline extension was caused by thousands of Serb civilians abandoning Prizren and other areas in a blow to Nato's hopes of maintaining a multi-ethnic Kosovo.

More than 15,000 Serb civilians have left Kosovo since last Wednesday, according to the UN refugee agency, UNHCR.

General Jackson appealed for them to stay, insisting that the Nato forces would protect them.

But the Serbs say Nato troops are doing nothing to disarm the KLA.

There have been numerous reports of marauding KLA soldiers looting Serbian warehouses, and torching Serb homes.

General Jackson said the KLA would be demilitarised, but the method had yet to be worked out.

As the Serbs leave, tens of thousands of Kosovo Albanian refugees are beginning to return, despite warnings that it is not yet safe because of mines..

The race to return home gathered pace on Wednesday, with long lines of cars backed up at border crossings.

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"They have been going in at the rate of 1,000 an hour since 7 am (0500 GMT)," said Andrea Angeli, spokesman for the Organisation for Security and Cooperation in Europe.