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Serbia says they had put up resistance and that the prisoners will be treated in compliance with the Geneva Convention on political prisoners.

But Britain has accused Serbia of acting in direct contravention of the Geneva Convention in taking the three captive and parading them for propaganda purposes.

The US says the GIs vanished in Macedonia, near the Serbian border

The British Army says that even though the conflict is not a war "as such", the conflict would indeed still be covered by the terms of the Geneva Convention.

In event of capture

Spokesman Michael Devlin was reluctant to go into operational details but he told BBC News Online that British soldiers are thoroughly trained in what to do in the event of capture.

He indicated that four key areas are:

• Do not disclose any useful information to the enemy
• Be aware of your rights as a political prisoner
• Make sure your captor is aware of your rights
• Maintain your morale

Knowledge of the Geneva Convention is an "essential part" of training, as are "conduct after capture" classes.

Vuk Draskovic, Yugoslav Deputy Prime Minister: "Nothing wrong could happen to the captives"

The spokesman said common sense and a sense of humour is very important - and soldiers must also be aware that they may be used as a propaganda tool.

The training, he added, has been shaped by lessons learned from the Gulf War, but more specifically from the Korean War and the Vietnam War - and there are still lessons to be learned from World War II.

Still doing their job

Soldiers who become prisoners of war are still considered to be working, according to a spokeswoman at the US Mission in Brussels - their job is to be good prisoners.

US military personnel take an oath not to do anything while being held captive to "embarrass" their country or be "detrimental to it".

Former SAS soldier Andy McNab, who was captured during the Gulf War and wrote the book Bravo Two Zero about his experience, agreed that the three men are still working.

They would have been trained to cope with captivity, although that training would not overcome the "initial fear and disbelief" of being taken prisoner, he said.

But once they are being interrogated, they would follow the procedure of only revealing limited information like their number, rank, name and date of birth.

Mr McNab said: "They don't want to appear aggressive to their captors, they don't want to appear being belligerent.

"But that's not to say that their minds are not working overtime to make sure they only give the correct information and still do their job, because they've still got a job to do," he added.

"Their job now is to be a prisoner and there are certain responsibilities to that."

The men would be encouraged because they were captured together and so there would be "a lot of hope and a lot of strength" shared between them, he said.

Treatment of PoWs

Key points of the convention regarding treatment of prisoners of war are:

• Every prisoner of war is bound to give only his surname, first names and rank, date of birth, and army, regimental, personal or serial number, or similar information.
• Prisoners must at all times be humanely treated.
• They must not be subject to physical or mental torture, mutilation or medical or scientific experiments.
• They must be protected against insults and public curiosity.
• They must be given free medical attention, and their upkeep must be free.
• Soldiers' identiy cards - showing the owner's surname, first names, rank, army, regimental, personal or serial number or equivalent information, and date of birth - may not be taken away.
• The questioning of prisoners of war shall be carried out in a language which they understand.
• All personal effects shall remain in their possession.
• Prisoners of war shall be evacuated, as soon as possible, our of the combat zone - and transported in a humane manner.
• Premises must be of a reasonable standard, in terms of heating, lighting, ventilation
• Food rations and drinking water must be sufficient.
• Smoking must be allowed.
• Suitable clothing, underwear and footwear and sanitary facilities must be provided.