Norwegian officials warned Thursday that there could be more arrests after at least seven Russians — including the son of a close associate of President Vladimir Putin — were detained in recent weeks for flying drones or taking pictures near sensitive areas, prompting an investigation by the domestic intelligence service. Norway and other countries are moving to secure critical infrastructure in the wake of the sabotage of the Nord Stream natural gas pipelines. Since then, drone sightings have been reported in Norway’s vast offshore oil and gas fields and at Norwegian airports. On Wednesday, Norway’s prime minister, Jonas Gahr Store,...
