BRUSSELS, Belgium - Europe's relationship with the Bush administration could begin with an angry row today over charges that the United States failed to warn allies of plutonium contamination in munitions.

European Union foreign ministers meeting in Brussels to discuss a wave of public concern about the alleged health risks of depleted uranium shells can expect to hear complaints by Germany that Washington had kept its European allies in the dark.

Portugal and Spain were also unprepared when the United States confirmed media reports and a Swiss laboratory finding that the "low risk" depleted uranium held minute traces of highly toxic plutonium and highly radioactive uranium 236.

If other EU states that belong to NATO feel they were inadequately informed to deal with the public furor over the depleted uranium shells, Defense Secretary Donald Rumsfeld's dealings with the allies may have a frosty start.

"It should be the duty of a friendly nation to inform their partner," German Defense Minister Rudolf Scharping told journalists on a weekend visit to Bosnia-Herzegovina and Kosovo to investigate use of the shells there.

NATO felt it was getting public concern over the shells under control until the presence of plutonium was disclosed.

Top medical officers from all 19 member nations' armies met in Brussels last week to compare data and announced a day later that there was no "Balkans syndrome" and no unseen health risk from the munitions.

The Pentagon had twice sent U.S. Army medical experts to NATO headquarters to help reassure the European media. But while the experts said depleted uranium was even less radioactive than natural uranium, they never mentioned plutonium.

On Thursday, Kenneth Bacon, Defense Department spokesman, said plutonium was detected in depleted uranium a year ago and a nuclear plant was shut for 90 days. "As you know, we discovered some stray elements . . . in depleted uranium," Bacon said.

"They consisted of plutonium, neptunium and americium. Now these are very, very small amounts, and as soon as they were discovered as indicating possibly a flaw in the production process, the Nuclear Regulatory Commission suspended the operation at this plant, which is in Paducah, Kentucky."

Despite a lack of evidence that depleted uranium has caused cancer among NATO peacekeepers serving in the Balkans, public concern had already prompted calls by some allies and by the European Parliament for a moratorium on use of the depleted uranium shells.

Depleted uranium shells are prized for penetrating armored tanks. About 40,000 rounds were fired in Bosnia and Kosovo, all by U.S. ground attack aircraft.

The United States, Britain and France have dismissed demands that they give up a military advantage on account of unfounded fears, and the Bush administration is not expected to waver.

Scientists say that inhaling one-millionth of an ounce of plutonium can cause a fatal cancer. That scares many people and frightens governments, as reaction to the latest developments indicates.

Scharping took scientists with him to the Balkans to make on-the-spot tests for plutonium. Spain ordered its medical experts to investigate. Switzerland said it would call for a total ban on depleted uranium shells at the United Nations this year.

A World Health Organization team was set to scour blast sites in Kosovo for traces of plutonium, and NATO member Portugal said the alliance must quickly back up assertions that the plutonium levels posed no health threat.