In its defence, the alliance has called on the world's media to put its bombing campaign in perspective, arguing that fewer civilians have been killed or injured in the Kosovo campaign than in any other comparable conflict.

As of June 1, Nato had carried out around 31,000 campaign flights over 70 days - around half of these being combat missions.

Speaking at Nato headquarters, alliance spokesman Jamie Shea said: "When we started this operation, we were conducting around 30 [sorties] a day. Now we are conducting up to 350 attacks every night.

"There has not been a ten-fold increase where bombs have gone astray.

"If anything, the proportion [of mistakes] is getting better. Better because Nato planners take every conceivable precaution to strike accurately."

These are the key Nato mistakes which have cost the lives of innocent civilians.

5 April: Homes hit
Cause of error: Missiles fall short

The 13th night of air strikes included the first major Nato blunder when an attack on a barracks on the southern mining town of Aleksinac resulted in missiles striking a residential area.
Serb TV reported at least five dead and at least another 30 injured when the three missiles fell 600m short of their target.
The missiles struck apartments, an "emergency centre" and a medical dispensary, TV reports said.
Commenting on the incident, Air Commodore David Wilby of Nato said "It is possible that one of our weapons fell short of the target.
"Despite our meticulous and careful pre-attack planning, the law of statistics will, at some stage, go against us and we will be exposed to technical defect."

Related story: 'Heaviest bombings yet'

12 April: Train destroyed
Cause of error: Timing

Russia and China lodged protests after Nato's raid on a railway bridge hit a passenger train, killing 10 and leaving 16 injured.
The Belgrade-Salonika train had been crossing the bridge near Leskovac, southern Serbia as the air-launched missile released several miles away reached its target.
Showing missile-cone video footage of the attack, Nato's commander of European forces Gen Wesley Clark said: "You can see if you were focusing right on your job as a pilot how suddenly that train appeared. It was really unfortunate."

Related story: When war goes wrong

14 April: Refugees bombed
Cause of error: Mistaken identity

After days of speculation, Nato leaders said the alliance was responsible for two attacks on Kosovo convoys, both of which might have included refugees fleeing western Kosovo.
The alliance said that its pilots had been hunting Yugoslav units burning out villages in western Kosovo but Serb media said the attack left 70 dead.
The picture was further muddied after it was revealed that a recorded debriefing of a Nato pilot, released to the media, was not the airman responsible for the strikes.
"This is a very complicated scenario and we will never be able to establish all the exact details," said US General Daniel Leaf.

Related story: Nato 'may have killed refugees'

27 April: Civilian homes struck
Cause of error: Imprecise targeting

Serbian officials reported that Nato killed at least 16 civilians after two missiles hit a residential area in the southern town of Surdulica.
The alliance said that it had struck an army barracks - but did not rule out civilian deaths.
Speaking at Nato HQ, General Giuseppe Marani said: "After more than 4,000 attack sorties, one bomb went astray. We put all our effort in avoiding collateral damage. "Things like this can happen and in fact they happened."

Related story: Nato strike kills civilians

28 April: Sofia hit
Cause of error: Stray bomb

Nato admitted that one of its missiles hit the Bulgarian capital Sofia after being fired in self-defence against a surface-to-air missile attack in Yugoslavia, 30 miles away.
No one was injured by the missile which hit a home in the Gorna Banja district. It was the fourth missile to land on Bulgarian territory.
Visiting the scene, Bulgaria's President Petar Stoyanov calmed residents saying no one had "expected such developments".
Explaining what had gone wrong, Nato spokesman Jamie Shea said: "After the ground radar was turned off the missile strayed from its target."

Related story: Sofia hit by missile

1 May: Bus bombing
Cause of error: Pilot did not see vehicle

At least 23 people died when a Nato missile aimed at the Luzane bridge north of Pristina hit a passenger bus.
News reports on Serb television showed that one part of the vehicle had plunged off the bridge while the rest had burned for more than an hour.
Nato's Colonel Konrad Freytag said: "Unfortunately, after the weapon's release, a bus crossed on the bridge but was not seen by the pilot whose attention was focused on his aim point during weapon trajectory".

Related story: Nato bomb hits bus

6 May: Cluster bomb hits Nis
Cause of error: Stray bomb

Nato admitted that a cluster bomb aimed at an airfield in the Yugoslav city of Nis hit a hospital and a market, killing 15 civilians.
Local officials said that a further 60 people were injured in the daylight attack which left unexploded cluster bombs lying in gardens.
Nato's Major General Walter Jertz said: "I can tell you that we did not target - repeat we did not target - civilian hospitals and we do not target any civilian targets whatsoever."

Related story: Nato bomb hits hospital

7 May: Chinese embassy hit
Cause of error: Mistaken identity

In the biggest mistake of the campaign to date, Washington admitted that an out-of-date map used by its intelligence operations had led Nato to launch missiles at the Chinese embassy in Belgrade, killing three people, injuring a further 20.
Nato said that the intended target had been the Yugoslav Federal directorate of Supply and Procurement 200 yards away.
Nato Secretary-General Javier Solana expressed deep regret over the "tragic mistake" and President Bill Clinton sent his condolences to China.
The attack provoked mass protests in China where its leaders have announced that unless Nato stops bombing they will veto any Kosovo peace plan put before the United Nations.

Related story: Embassy Strike 'a mistake'

May 13: Kosovo village bombed
Cause of error: Nato defends action

At least 100 civilians died after Nato bombed what it said were "legitimate military targets" in the village of Korisa, southern Kosovo.
Footage broadcast by Serbian TV showed charred remains, including at least two children, smouldering homes and burning tractors.
The BBC's correspondent in Pristina, Jacky Rowland, reported that forensic teams were trying to piece together human remains to establish the exact death toll.
The alliance rejected reports that it had used cluster bombs - a weapon designed to target humans.
In a statement, Nato said that it deeply regretted any accidental civilian casualties and that military equipment had been seen in the area.

Related story: Village 'legitimate target'

May 19: Belgrade Hospital struck
Cause of error: Missed target

Serb officials say that a Nato bombing attack led to the deaths of at least three patients in a Belgrade hospital.
Parts of the Dragisa Misovic hospital, near a barracks in the Dedinje district, were reduced to rubble.
State television reported that emergency services evacuated infants and pregnant women. One woman was in labour when the bombs hit, the report said.
Serbian Deputy Premier Milovan Bojic said that Nato's actions had been "something history and mankind would never forget".
Nato's spokesman Jamie Shea said the weapon missed its target by 1,500ft because of technical reasons.
He said that Nato had no information on civilian damage.

Related story: Nato hits hospital

May 30: Civilians die on bridge
Cause of error: Civilians caught in "legitimate bombing"

At least 11 civilians were reported killed and a further 40 injured when Nato bombers mounted a daylight raid on a bridge in Varvarin, south-central Serbia.

Yugoslav news agency Tanjug said local people were attending the town's market when the attack happened at 1pm local time.

Witnesses said four cars fell into the River Velika Morava. Rescuers who went to aid of the injured were hit in the second attack.

Nato spokesman Jamie Shea said the alliance had bombed a ""legitimate designated military target".

"There is always a cost to defeat an evil," he said. "It never comes free, unfortunately. But the cost of failure to defeat a great evil is far higher," said Nato spokesman Jamie Shea.

Related story: Civilian deaths "necessary price"

May 30: Nato hits old people's home
Cause of error: Misguided bombs

Yugoslavia reported that at least 20 people lost their lives when Nato bombs hit a sanotorium and neighbouring old people's home in Surdulica, south-east Serbia - the second loss of civilian life in the town since bombing began.

Nato spokesman General Konrad Freitag said that warplanes struck an ammunition storage depot and a military barracks.

"Nato cannot confirm any Serb claims of casualties or collateral damage," he said. Earlier, Tanjug said that Nato hit a car carrying western journalists in Kosovo.

The driver of the car, an interpreter, was killed in the explosion. The passengers, an Italian, French and British journalist - Eve-Ann Prentice of The Times newspaper - suffered injuries.

Related story: Nato 'hit old people's home'

May 31: Apartment block struck
Cause of error: Bomb overshoots target

In the third Nato blunder in 26 hours, alliance missiles hit an apartment block in Novi Pazar, south-west Serbia, killing at least 11 people and injuring a further 23 residents.

Tanjug said that 20 missiles fell on various targets in Novi Pazar with the apartment taking a direct hit. More bodies were believed buried in the rubble.

The news agency also reported that Nato's targets had included a publishing house, printing presses and regional television and radio headquarters close to a hospital and a bus station.

Nato admitted that a bomb went astray during an attack on an army barracks.

Alliance spokesman Jamie Shea said that five out of six munitions hit the target but one overshot its by about 60 metres.