German Police Confirm Seizure of Nuclear Fuel Smuggled From Russia : Europe: Cache on flight from Moscow was third found this year. Officials think it was headed for black market.

German police have made their third and largest seizure this year of weapons-grade nuclear material apparently smuggled from the former Soviet Union for sale on the world black market, officials said Saturday.

Bavaria state police in Munich confirmed reports by the weekly magazines Der Spiegel and Focus that they confiscated a stash of highly enriched plutonium hidden in the suitcase of a passenger on a Lufthansa flight from Moscow on Wednesday.

German media reported that three suspects, two Spaniards and a Colombian, were arrested.

The seizure supports warnings by U.S. and German officials of a growing post-Cold War black market in radioactive materials. German authorities say their country is a primary transit route for the smugglers, and they suspect that the buyers of the nuclear materials could be terrorist organizations or the governments of Iran, Iraq, Libya or North Korea.

“This is a grave danger, not only for us but for many (countries),” Chancellor Helmut Kohl told the German television network ZDF.

On a trip through Germany, Poland and Russia in early July, FBI Director Louis J. Freeh called nuclear smuggling operations “the greatest long-term threat to the security of the United States.”

The exact quantity of plutonium confiscated Wednesday was still uncertain, but it was at least 10 times as great as the previous find and potentially worth millions of dollars.

Police said experts at a European atomic research institute in Karlsruhe were examining 100 to 300 grams of what could be pure plutonium-239, which can be used to build a nuclear bomb.

Der Spiegel reported that 500 grams of a “fine dark-brown powder” was confiscated by police but that nuclear experts had indicated only about 50 grams of it was usable for nuclear weapons. Final test results are not expected for several days.

About three to five kilograms--approximately seven to 11 pounds--of plutonium are needed to build an atomic bomb, according to one scientific expert.

“Of course the worry is that it might be we only catch one of five (shipments) and they all have the same buyer,” the expert said.

German authorities have handled about 250 cases involving supposed radioactive substances since the collapse of the Soviet Union. All but three turned out to be scams in which con men were trying to peddle fake bomb material.

The three exceptions, however, have alarmed officials.

Last May, police in the southwestern state of Baden-Wurttemberg arrested businessman Adolf Jaekle on suspicion of counterfeiting and found six grams of nearly pure plutonium-239 in his garage. Tests showed that the sample was of Russian origin, probably from a nuclear weapons factory.

On Thursday, Bavarian police announced that during June and July they arrested five East European men and a German woman for smuggling one gram of enriched uranium-235, believed to have come from a Russian nuclear power station or submarine. The woman, a real estate agent, was believed to be the leader of that smuggling band.

Several German media reported Saturday that a police informant helped obtain the most recent arrests at the Munich airport.

Der Spiegel quoted German intelligence officials as saying that the operation possibly had been organized by Libyan, Iranian or Iraqi diplomats.

Police said the plutonium was carried in a lead-lined steel box and that no passengers, flight crew or ground crew had been exposed to danger.

It is not known if the three seizures in Germany are related. The exact sources of the nuclear materials are unknown, although all are believed to have come from Russia or the former Soviet republics.

Germany’s DPA news agency said Russian government agencies had no information on the most recent seizure.

“Up to now, not a single plutonium loss has been recorded,” one Russian official told DPA.

But Russian police also have announced several arrests and seizures of nuclear materials.

Kohl said he wrote to Russian President Boris N. Yeltsin on the issue before leaving for vacation in Austria last month and that the two will speak about the issue when Kohl returns.

“I will also very quickly send an envoy to him to find out what we can do to establish once and for all where these things come from. We do not know this. Secondly, every possible step must be taken to prevent such things from happening in the future,” Kohl said.

Poorly paid workers at former Soviet nuclear facilities are among those suspected of selling the nuclear material. The smuggling is being done by low-level criminal gangs willing to peddle anything from narcotics to currency to weapons, authorities say. But they also fear that organized crime in Russia or Italy will get into the business.

Der Spiegel reported that the Russian deputy minister for nuclear energy, Viktor Sidorenko, was aboard the flight from Moscow on which the latest stash was discovered. He was flying to Germany to meet with Bavarian officials about civilian nuclear projects.

A police spokesman would not comment on whether Sidorenko was a suspect in the smuggling, but one source said his presence was believed to be an “ironic coincidence.”