Martin Korch, the police spokesman from Slovakia had said the three were about to sell the unspecified radioactive material. They were trying to sell it in Slovakia for one million US dollars.
Two of them were arrested in Slovakia. The third one was arrested in Hungary.
Korch explains that experts are examining the material the three tried to sell to determine exactly what the stuff is. The three have been arrested in the eastern parts of both Slovakia and Hungary nearing the border of Ukraine.
This story came into BBC News at 18:25 GMT