[BBC] Days of sightings of drones over key Swedish sites including nuclear plants have prompted the country's security service to take the lead in an investigation.Three nuclear sites have been targeted and sightings have been reported over airports and the royal palace.Authorities have not speculated on who is behind the mysterious drones.
Police and the coastguard are searching the sea and islands around Stockholm, local media reports say.
The latest sightings on Monday evening involved a drone above the Forsmark nuclear plant, but security agency Sapo said it was also investigating earlier drone flights near the Ringhals and Oskarshamn power plants. Police appealed to the public to come forward with information.