Customs was alerted by a warning system that detected background radiation levels 20 times the norm in the departures hall. A passenger’s bag was then searched.

Metallic objects found packed into steel boxes proved to be the radioactive isotope Sodium-22, which had been machine-produced, the Russian customs service said.

“Tests showed that the Sodium-22 could only have been obtained as the result of the work of a nuclear reactor,” a statement from the Russian customs service revealed. “A criminal enquiry has been opened and the materials transferred to prosecutors.”

Russia built Iran’s first nuclear power station in the southern city of Bushehr (pictured above), and has delivered the nuclear fuel for the reactor.

However, Moscow has in the past echoed Western concerns about the exact nature of Iran’s nuclear programme, though it has never publicly accused Tehran of seeking atomic weapons.

There have recently been calls for tighter controls as regards the smuggling of nuclear-associated materials, so that Iran cannot get hold of the sort of materials it is banned from obtaining under UN Security Council sanctions.

Photo: Getty