Military sources said a paratrooper shot dead a man brandishing a gun.

An army officer said the paratrooper from 1 Battalion had been on foot patrol when a man waving a pistol came out of a building.

He was wearing civilian clothes but, according to the sources, he was a Serbian special policeman.

He was asked six times to put the weapon down and refused before firing a shot in the general direction of the soldier.

The source said the paratrooper then returned fire, killing the man instantly.

'A proper job'

Earlier, there were scenes of wild celebration as British tanks from 4th Armoured Brigade rolled into the Kosovan capital of Pristina after a night of gunfire and civil unrest.

They chanted: "Nato, Nato," and gave bunches of flowers to soldiers or threw them onto armoured patrol cars. As Serb soldiers and civilians left the city, they were jeered by the Albanians.

The first Warriors arrived in Pristina at around 1000 BST. They are holding major road junctions and patrolling the major streets. The troops were pleased to be treated to the rapturous reception after a tense night.

"There have been just loads of people coming up to us being really friendly. It feels great. It feels like I am doing a proper job," said the youngest soldier in Irish Guards, 17-year-old Ben Noble, from Wandsworth, south London.

More than 10,000 Nato troops - half of them British - are expected in Kosovo by Sunday night.

Their task will be far from easy. The Albanians may be delighted to see them, but the Serbs are not so enthusiastic and yet Nato is keen to win the trust of both sides.

And tension between the Albanian and Serb communities are already building up. On Saturday night there were reports that three Serb policemen had been shot dead just outside the city.

But troops played down the incident.

"Some Serbs have been coming up to us and making clear they do not want us to be here but it was just a bit of verbal abuse and one of them started kicking the wagon - it was a pretty futile gesture," Lieutenant Richard Rous, 23, of Haslemere, Sussex.

"I have heard reports of some people pulling soldiers and trying to grab their weapons but I have not seen them."

Brigadier's fury

Back at Pristina airport the stand-off between British and Russian troops continues.

Brigadier Freer with his Russian T-shirt

A furious British Army commander, Brigadier Adrian Freer, shouted at sentries holding up the British advance.

"What the hell are you doing here? Get on to your commanders and get out of here now," he told them.

He then pulled down the collar of his uniform to show a pale blue and white striped Russian Airborne Division T-shirt to show he was a comrade not an enemy. He had been given the T-shirt by Russia's Major-General Valerie Ribkin after talks to carve up the airport, a strategic site.

Brigadier Freer had been assured the airfield could be split in two dividing the north section for the Russians and the south for the British with dual use of the single runway.

"I found the general very pragmatic and pleasant but the decisions affecting the situation now appear to be above both of our pay grades, said the brigadier.

"I thought we had reached an agreement on gaining access to the airport but I can only assume that their chain of command is much more rigid than ours and the orders have yet to come through."