Nato chiefs were last night facing Europe-wide calls for an investigation into the safety of depleted uranium ammunition used by US pilots in the Kosovo war, following Italian claims linking the cancer deaths of five of their peacekeepers.

The allegations have put Britain's Ministry of Defence under new pressure to re-examine links between the use of depleted uranium ammunition and health problems suffered by servicemen who fought in both the Gulf War and in the Balkans.

The revelation yesterday that Italy's military prosecutor is examining five fatalities among 20 cases which the Italian media is linking to a so-called 'Balkans syndrome' - similar to Gulf War Syndrome - follows concern in both Belgium and Portugal last week.

Depleted uranium has been a source of controversy for over a decade amid claims that its contamination of battlefields in Iraq has caused widespread cancer among Iraqi civilians and contributed to health problems among allied military veterans of the Gulf War.

Belgian Defence Minister André Flahaut called on Friday for EU Defence Ministers to examine the issue. This followed reports that Portugal's Ministry of Defence had ordered medical tests for its soldiers serving in Kosovo to check for radiation.

US attack jets are thought to have fired more than 31,000 rounds of depleted uranium ammunition - used to pierce armour - at Serbian tanks and armoured cars.

Last night a spokesman for the MoD in London said: 'It is toxic in much the same way that lead is toxic, and it has a very low level or radiation. In its solid form it poses no great risk.

'There is more cause for concern when it is fragmented and can be inhaled. For that to happen it would have to hit a fairly hard target, like a tank. Then, if a soldier were to enter an overturned tank immediately afterwards they might be at some risk. But it quickly disperses. A year on we believe it would pose no risk at all.'