He said they had the same symptoms as some veterans of the 1991 Gulf war.

But he found no trace of the depleted uranium (DU) some scientists believe is implicated in Gulf War syndrome.

Other researchers suggest new types of radioactive weapons may have been used in Afghanistan.

The scientist is Dr Asaf Durakovic, of the Uranium Medical Research Center (UMRC), based in Canada.

Dr Durakovic, a former US army adviser who is now a professor of medicine, said in 2000 he had found "significant" DU levels in two-thirds of the 17 Gulf veterans he had tested.

In May 2002, he sent a team to Afghanistan to interview and examine civilians there.

The UMRC says: "Independent monitoring of the weapon types and delivery systems indicate that radioactive, toxic uranium alloys and hard-target uranium warheads were being used by the coalition forces." There is no official support for its claims, or backing from other scientists.

Shock results

Bomb damage was widespread

It says Nangarhar province was a strategic target zone during the Afghan conflict for the deployment of a new generation of deep-penetrating "cave-busting" and seismic shock warheads.

The UMRC says its team identified several hundred people suffering from illnesses and conditions similar to those of Gulf veterans, probably because they had inhaled uranium dust.

To test its hypothesis that some form of uranium weapon had been used, the UMRC sent urine specimens from 17 Afghans for analysis at an independent UK laboratory.

It says: "Without exception, every person donating urine specimens tested positive for uranium internal contamination.

"The results were astounding: the donors presented concentrations of toxic and radioactive uranium isotopes between 100 and 400 times greater than in the Gulf veterans tested in 1999.

"If UMRC's Nangarhar findings are corroborated in other communities across Afghanistan, the country faces a severe public health disaster... Every subsequent generation is at risk."

It says troops who fought in Afghanistan and the staff of aid agencies based in Afghanistan are also at risk.

Scientific acceptance

Dr Durakovic's team used as a control group three Afghans who showed no signs of contamination. They averaged 9.4 nanograms of uranium per litre of urine.

The average for his 17 "randomly selected" patients was 315.5 nanograms, he said. Some were from Jalalabad, and others from Kabul, Tora Bora, and Mazar-e-Sharif. A 12-year-old boy living near Kabul had 2,031 nanograms.

Troops and aid workers could be at risk

The maximum permissible level for members of the public in the US was 12 nanograms per litre, Dr Durakovic said.

A second UMRC visit to Afghanistan in September 2002 found "a potentially much broader area and larger population of contamination". It collected 25 more urine samples, which bore out the findings from the earlier group.

Dr Durakovic said he was "stunned" by the results he had found, which are to be published shortly in several scientific journals.

Identical outcome

He told BBC News Online: "In Afghanistan there were no oil fires, no pesticides, nobody had been vaccinated - all explanations suggested for the Gulf veterans' condition.

"But people had exactly the same symptoms. I'm certainly not saying Afghanistan was a vast experiment with new uranium weapons. But use your common sense."

The UK Defence Ministry says it used no DU weapons in Afghanistan, nor any others containing uranium in any form.

A spokesman for the US Department of Defense told BBC News Online the US had not used DU weapons there.

He could not comment on Dr Durakovic's findings of elevated uranium levels in Afghan civilians.