Nato leaders may feel sensitive about the recent civilian disaster in Kosovo, but there has been no break in their military campaign.

The air strikes are Nato's only strategy, and they have to succeed.

Nato officials are determined to continue the campaign

When they go wrong, the alliance can only apologise and press on.

Thursday's briefing at Nato headquarters left a message that was clear but uncomfortable: that however well guided the weapons, however careful the pilots, it is almost inevitable that civilians will become victims.

"Although the crews have specific orders not to attack civilian targets, the intense air campaign will inevitably result in loss of life among innocent civilians and damage to civilian structures," said Nato General Giuseppe Marani.

Civilian casualties more likely

It is an awkward fact, but since cruise missiles opened the campaign three weeks ago, civilian casualties have become more rather than less likely.

The pilot's job becomes ever harder

Alliance leaders have had to brace themselves for the aftermath.

The first targets were air defences and military headquarters, and the weapons seemed generally to have struck with great accuracy.

Serb television made great play of severe damage. But at that stage, reports of civilians being harmed were few and far between.

That changed with the next phase of the campaign, when fuel installations and bridges were attacked all over Yugoslavia.

Suddenly Nato action was carried to the lives of ordinary Serbs, people with who the alliance says it has no quarrel.

It is the attacks on Serb forces in Kosovo, the hunts for the units harassing the Albanians that carry the greatest hazards.

Military and civilians are bunched together and telling one from the other from the air can be difficult.

"You can't see that it is a tractor or vehicle markings or anything. You can see that it is a vehicle and it is what you are attacking," said Gulf War veteran, John Nichol.

Targets get smaller

As the air campaign intensifies, the pressure for results has never been greater. The risk to civilians is growing.

The targets are becoming increasingly small and mobile: lorries, tanks and armoured personnel carriers.

The great dread in the Nato briefing room is that more apologies will have to be made before the campaign can be said to have succeeded.

The air strikes can only continue with the support of all 19 Nato governments.