Portuguese soldiers who served with the United Nations peace-keeping force in Kosovo last year could have suffered radiation poisoning, according to scientists investigating the claim.

The defence ministry has announced some 900 troops who formed part of the UN operation will undergo tests. There are fears that some soldiers have become ill or even died after being exposed to depleted uranium used in ammunition.

"We don't know the level of contamination", said Fernando Carvalho from the Nuclear Technology Institute, "so it's difficult to say if it's too late to act."

"Perhaps it's not as serious as it looks at the moment. In that case, we can probably act now to make a difference. But if there's been widespread contamination, questions will be asked why we didn't do something sooner."

As the tests get underway, the father of a Portuguese soldier who died shortly after serving in Kosovo has ordered his son's body to be exhumed and tested for radiation poisoning.

It is a sensitive issue, and not only in Portugal. An Italian soldier returning from duty in the region also died mysteriously. As government ministries and military authorities act belatedly, they are being accused by the media of trying to cover up the issue.