It produced a US Air Force commander from Nato's theatre of operations at Aviano air base in Italy at a crowded press conference in Brussels.
Demonstrating the alliance's determination to bring to a close Nato's biggest public relations disaster of the four-week air campaign, he gave an apparently full and frank description of how F-16 and Jaguar aircraft targeted two different convoys near the town of Djakovica.
Brigadier General Dan Leaf gave a detailed account of last Wednesday's tragedy, using video imagery from aircraft and a transcript of pilots' radio conversations.
The flight-suited general, who has flown many combat missions over Yugoslavia, said he had spent five days assembling and analysing the evidence of the day Nato warplanes attacked two target areas in Kosovo, dropping nine 500lb laser-guided bombs. He said: "It is possible there were civilian casualties at both locations."
The explanation did clear up some of the worst contradictions between Nato's first muddled account, the evidence produced by Serbian television and statements from refugees who survived the bombing.
But the general was still unable to identify exactly how many civilian vehicles were hit by Nato planes, and how many casualties had been caused. "This is a very complicated scenario and we will never be able to establish all the exact details," he said.
General Leaf also suggested that some of the destruction seen on Serbian television, and witnessed by bussed-in Western reporters, may have been caused by the Serbs themselves. "I cannot explain the bodies shown on Serb TV," he said. Belgrade claimed that Nato killed more than 80 ethnic Albanian refugees, though the journalists taken to the scene said many bodies appeared to have been killed by machine-guns or mortars. The general insisted the planes involved in the attack had used laser-guided bombs.
The general accepted responsibility for some of the casualties and appealed for the public's understanding.
"The world knows that battle is a complex, dynamic and demanding environment," he said. "For all our efforts, we will never be perfect. We don't claim to be perfect, we claim to be dedicated to do the best job possible."
Nato's newest and fullest explanation of the convoy bombing raised fresh questions about air crews' ability to identify targets safely. Reports that pilots from RAF Harriers had warned that civilian vehicles were among one of the convoys have not been denied.
One source said this information may have been sent to the airborne command and control centre rather than direct to the F-16 pilots involved in the attack, and that this fatal delay was one reason for the disaster.
General Leaf admitted that on 14 April, Nato made two separate attacks on convoys. That explained the confusion over the release last week of a tape of a pilot's debriefing, produced by Nato, which referred only to one attack at 10.30am. That was north-west of Djakovica by an F-16 which had been ordered to find and attack enemy forces.
The pilot saw "very graphic and very horrifying" evidence of burning villages, then watched figures leave one house, get into a vehicle and drive away. He concluded that the vehicle was involved in the attacks.
He launched a laser-guided GBU-12 bomb, and called in a second aircraft. After a 10-minute reconnaissance, the second aircraft made a second attack on vehicles parked in a C-shaped farm courtyard. Yesterday Nato still insisted it was correct to target these vehicles.
The second, more serious incident was south-east of Djakovica, where a very large convoy was spotted by another F-16 pilot. General Leaf said the "20 vehicles were uniform in shape and colour. They were maintaining steady spacing and pace, characteristic of military movement".
When the pilot consulted airborne command and control, he was told: "We just received word that this is a VJ [Yugoslav army] convoy". That attack began at 12.19 and was suspended at 12.58, after the command and control centre in Italy ordered new checks on the identity on the composition of the convoy.
The attack was aborted when more sophisticated reconnaissance from an OA-10 aircraft revealed that there was a mix of civilian and military vehicles.
General Leaf said he watched the video tape of the attack with the crews involved, and they agreed "it is possible these were tractor-type vehicles", but he added: "From the attack altitude, to the naked eye they appeared to be military vehicles."Reuse content