According to Ukraine's Border Guard Service, the man was detained at Kiev's Boryspil International Airport on Saturday after a radiation detector went off in the baggage checking area.
"As a result of the controlled measurement by representatives of environmental monitoring services, the level of radiation of the baggage, measured by a dosimeter, was determined at a level of 2.5 millisieverts per hour," a statement on the border security services' website noted. Russian news hub Lenta.ru explained that this level of radiation is 6,000 times above normal levels.
After examining the man's baggage, border security agents determined that the source of the radiation was a tabletop clock released in 1984. The man explained that he had purchased the clock at a local market. Local security authorities have been informed of the incident.