Security at Sweden's three nuclear power plants has been tightened after explosives were found on a truck at Ringhals atomic power station in the south-west of the country.
Sniffer dogs detected the material in a routine check on Wednesday. Police declined to describe the amount or type of explosive discovered but said they were investigating possible sabotage.
Technicians said there was no detonator, and no imminent danger of an explosion.
The Ringhals plant, 70 kilometres south of Goteborg, houses four reactors controlled by the Vattenfall and E.ON energy companies. Police said they were investigating possible sabotage but had no suspects. The Swedish Radiation Safety Authority said the explosives were found on the truck "en route from the Ringhals industrial park into a protected area ... and did not enter the facility".
Sweden's 10 nuclear reactors at three power plants – Ringhals, Forsmark and Oskarshamn – provide about half of the nation's electricity.
In 1980, the country voted in a referendum to phase out the use of nuclear energy. But the centre-right government overturned that decision two years ago, citing the lack of viable long-term, environment-friendly alternatives.