Three Croatian nationals have been arrested in Serbia after radioactive material was discovered in their car, local media report.
They were about to enter Croatia on Saturday when scanners detected a “serious amount” of radiation.
During a subsequent search of an Audi car, the head of a radioactive lightning rod was found in the spare tyre, reports say.
Serbian officials are continuing to question the three suspects.
The incident occurred at the Bezdan border crossing near the town of Sombor on Saturday at 20:30 (19:30 GMT).
There has been no detail about the amount of radioactive material involved or its potential impact, but workers at the border crossing were ordered to discard their clothing and undergo medical checks as a precaution, Serbian media report.
Experts from Serbia’s Vinca nuclear research institute have reportedly moved the head of the lightning rod to a safer place.
Hundreds of thousands of radioactive lightning rods were installed worldwide in the past few decades, according to the International Atomic Energy Agency (IAEA), in the belief that they enhanced the chance of lightning strikes hitting the rods and not nearby targets.
In a report last year, the IAEA said that “no convincing scientific evidence has been produced to demonstrate increased efficacy” and many countries had decided to stop the production of these devices. Some have started to remove the radioactive sources from the lightning rods that have already been installed.
However, the report suggested most of the rods were installed more than 50 years ago, when nuclear safety standards had not been introduced.
No reliable data existed about their overall numbers or location, it added, let alone the state of wear and tear or decay of the protective cases or the radioactive material contained inside. It highlighted cases where rod heads were sold as scrap metal by traders unaware of their existence or danger.
