Russia's customs agency seized 18 pieces of radioactive metal at Moscow's Sheremetyevo airport from the luggage of an Iranian passenger bound for Tehran. The pieces of metal, packed in steel pencil cases, contained large quantities of a radioactive isotope of Sodium-22. Although its intended use was unknown, experts noted that the material, while unsuitable for use in a nuclear weapon or dirty bomb, could be used as a calibration source for radiation instrumentation.