Police said Wednesday three people have been arrested for attempting to sell a small amount of an unspecified nuclear material.
Police spokesman Martin Korch said specialists were examining the radioactive material seized in Slovakia. He said the three allegedly planned a deal to sell the material, which weighs a kilo, or 2.2 pounds, for $1 million.
Two of the suspects were arrested in eastern Slovakia, the other in Hungary. All three were in areas near the border with Ukraine.
Korch said the material was being examined and did not confirm a report carried by the Slovak news agency SITA that it was enriched uranium. Uranium enrichment can yield either fuel for nuclear power stations, or be used for nuclear warheads.
The suspects were not identified.
Korch said Slovak and Hungarian police have been working together on the case for several months. He declined to give any further details, saying they would be released on Wednesday.
There have been concerns that Eastern Europe could be a source for radioactive material for a so-called "dirty bomb."
In 2003, police in the neighboring Czech Republic arrested two Slovaks in a sting operation in the city of Brno, after they allegedly sold undercover officers bars of low-enriched uranium for $715,000.