Six people have been arrested in Moldova and accused of trying to sell weapons-grade uranium, news reports said Thursday.
Authorities seized more than a kilogram of uranium-235, which can be used to build a dirty bomb, authorities in the capital, Chisinau, were quoted as saying in Russian news reports.
A dirty bomb does not produce a nuclear explosion but can contaminate a large area with radioactive material, DPA reported.
Authorities said they suspected the uranium was intended for a customer from a North African country. The investigation had been helped by tips from the German police and authorities in the United States, they said.
The suspects included citizens of Moldova and Russia as well as Arab and African countries, the reports said. The uranium was found in the apartment of one of those detained.
In another incident in August, Moldovan authorities arrested three men allegedly attempting to sell 1.8 kilograms of uranium-238, a more stable and commonly found isotope of uranium that can be processed into uranium-235.
The men were suspected of trying to sell the material for almost 9 million euros (13 million dollars) on the European black market.
Since the collapse of the Soviet Union in 1991, the risk of uranium from old nuclear plants finding its way onto the black market has risen.