Enough is enough - Owen: Calls for action after shooting down of Sarajevo flight. Robert Fisk and Tony Barber report

BOTH the United Nations and the Italian government concluded last night that the Italian aid aircraft that crashed on the way to Sarajevo on Thursday afternoon was shot down by at least one ground-to-air missile.

Lord Owen, the former Foreign Secretary who heads the European Community's mediation efforts in the former Yugoslavia, warned yesterday that the UN Security Council would respond with severity to such an attack.

'There sometimes comes a moment when the world looks at a situation and says that enough is enough. Maybe this might prove to be it,' he said.

Lord Owen said that the Security Council would probably pass a resolution insisting on a halt to all military flights over Bosnia and surrounding areas, and demanding that the warring parties place their heavy weaponry under UN supervision.

More cautious, and apparently contradictory, words emerged from Washington last night. The US Secretary of Defense, Dick Cheney, said he did not know if the plane had been shot down. But the acting Secretary of State, Lawrence Eagleburger, said he believed the plane was attacked. 'We have to provide humanitarian assistance and we will use force if necessary to provide that assistance,' he said.

All aid flights to Sarajevo were cancelled yesterday. The Italian Prime Minister, Giuliano Amato, said the flights to Bosnia should not stop but called on the UN to give them more effective cover. He said he did not believe that the UN and Italy could decide 'that the people of Bosnia should cease to eat. But we cannot permit our men to be exposed defenceless to the danger of being shot down.'

French troops who reached the scene of the crash yesterday and recovered the bodies of the four-man crew, discovered that the wreckage was scattered over a wide area - suggesting that the plane disintegrated in the air after being hit by a missile.

The G-222 aircraft was flying over the Croatian-Serbian front lines when it disappeared from radar screens. Initial suspicion among UN officials fell upon Muslim or Croat forces. 'When something like this happens, you have to ask yourself who gains?' an officer commented acidly.

'The Croats and the Muslims want more international involvement. Now we have to ask: do we use fighter aircraft as escorts for the relief planes?'

Four US helicopters came under small-arms fire on Thursday night as they attempted to reach the crash scene.

As cancellation of the aid flights was announced, UN relief agencies in Geneva launched an appeal for pounds 220m to meet humanitarian needs in the former Yugoslavia. A Bosnian representative said it was estimated that more than 100,000 people could die in Bosnia next winter.

He said: 'In Sarajevo most window panes are broken. Practically 400,000 people will meet the winter as though they were living on balconies.'

(Map omitted)