War In The Balkans: Refugees lie slaughtered in the road. But who takes the blame? are their killers? killed them?

NATO AND Serbia traded accusations last night over who was responsible for a rocket attack on two refugee convoys in Kosovo that killed at least 60 Albanian civilians.

Accusing Nato of a "crime against humanity", the Serbs said allied jets attacked the convoys of tractors and cars travelling under Serb "escort" yesterday between the western cities of Prizren and Djakovica, and arranged for a Reuters photographer to visit the scene.

The photographer filmed blood-stained bodies lying on a road near abandoned tractors. Pillows and blankets were scattered around as well as human remains.

The Serb Media Centre, based in the Kosovo capital of Pristina, said the first column of about 1,000 Albanians was hit twice near the village of Meja, close to Djakovica, while the second smaller column was hit on the road between Prizren and Djakovica. "In the village of Meja, 64 people were killed and 20 wounded including three Serb policemen who were escorting the convoy," it said. "In the village of Zrze, six people were killed and 11 wounded."

Belgrade exulted openly over what it hopes will prove a fatal Nato blunder. "I don't think those people in Brussels are going to get away with this," said Miodrag Popovic, Serbian Information Minister.

But the Pentagon insisted Nato had struck a military convoy on the Prizren- Djakovica road and suggested the Serbs themselves had bombarded another convoy travelling behind their vehicles in retaliation, or had attacked the refugees on the ground.

The Pentagon spokesman, Kenneth Bacon, said Nato planes had hit a Yugoslav army convoy at 15.30 local time. The pilots had been questioned "and believe they hit only military vehicles". But Nato had also received "verbal reports" that after the convoy was hit, Serb military personnel "got out and attacked civilians ... there may be imagery, film, of that".

The Pentagon said later, quoting Nato, that the pilots had cut short their attack on the convoy when they realised it contained civilians and believe they struck only the military targets. The US claims will revive fears that the Serbs are employing Albanian civilians in Kosovo as "human shields" against air strikes. Washington believes the Serbs are using the forced deportations of Albanians to move tanks and other military equipment around the province and that the refugees are "tacked on", or sandwiched in between, the Serb army vehicles.

In Brussels, the alliance admitted attacking "military targets" in the Prizren-Djakovica area but said it would need to scrutinise the film brought back by the returning planes before making further comment.

Nato's spokesman, Jamie Shea, said it was possible the Serbs had carried out the attack themselves, as they had been using low-flying aircraft in the province.

International observers in Albania, based over the border from Djakovica, expressed some scepticism at the Serbian version of events. They said the refugees' reports were confused and could mean either Serbia or Nato was responsible. "We are hearing that a helicopter went by and threw grenades out; we're hearing reports that a MiG flew by and bombed the column," said Owen O'Sullivan, a monitor with the Organisation for Security and Co-operation in Europe, based in the northern Albanian town of Kukes.

The monitor said he was "most surprised" that none of the wounded civilians had crossed into Kukes, as the town is so near the scene of the reported attack.

Refugees who did cross the Albanian border at Morini last night confirmed they had seen the ruins of the convoy but did not know who was responsible. One man said: "We saw the destroyed tractors by the side of the road. There were at least 10 bodies. Some did not have heads or arms or legs." He added: "There were three planes in the attack, but we did not see them well enough to know what sort they were." However, another man crossing later claimed the convoy was attacked by Serbian MiGs

Tony Blair said he feared a human tragedy was being manipulated by the propaganda machine of the Yugoslav President, Slobodan Milosevic. "You can't take at face value any claim made by the Serb authorities; everything they do, they use for propaganda purposes," he said. "We go to extraordinary lengths to avoid civilian casualties at all times. The responsibility for anything that happens to people in this conflict rests with Milosevic."

If Nato does turn out to have massacred the Kosovars, it will - at least temporarily - deal a big blow to the alliance's credibility and undermine its claim to be taking the greatest possible precautions to avoid civilian casualties. It will also embarrass the guerrilla fighters of the Kosovo Liberation Army who have been working in close connection with Nato and supposedly informing it of potential targets in Kosovo.

Yesterday's reported attacks follow Monday's mistaken strike on a train near the southern Serbian town of Leskovac, in which 27 civilians are now said to have been killed.

Nato's Supreme Commander, General Wesley Clark, said it was an "uncanny accident" that a train was crossing the bridge at the very moment Nato was trying to bomb it.

While the alliance was put on the defensive, the spotlight was entirely taken off the Serbs' continuing campaign of ethnic cleansing in the province. Yesterday the Serbs herded another 3,000 Albanian civilians to the frontier with Macedonia.

The United Nations High Commissioner for Refugees, Sadako Ogata, said 525,000 Kosovo refugees were now outside Kosovo, but it was not known how many remained inside. "We don't know exactly how many there are because many of them have left, and were forced to leave," she said.