A Norweigan court on Friday ordered a 50-year-old Russian national held in custody for two weeks as he admitted to flying two drones over the country, potentially over critical energy infrastructure.
In recent weeks, there have been numerous drone sightings near the country's offshore oil and gas platforms.
Security has been ratcheted up following explosions that targeted gas pipelines in the Baltic Sea last month.
What do we know about the suspect?
The identity of the Russian male was not made public, only that he was detained on Tuesday with three passports in his luggage, two Russian ones and one Israeli, according to local Norweigan media.
Authorities also seized four terabytes of data, some of it encrypted.
Customs officers reportedly located two drones and numerous electronic storage devices during a routine check at the border crossing in Storskog, the only border crossing between Norway, a NATO member, and Russia.
The border between Russia and Norway is 198 kilometers (123 miles) from Arctic land.
Prosecutor Anja Mikkelsen Indbjor told Norwegian broadcaster NRK that the Russian man is suspected of violating sanctions that were put in effect following Russia's invasion of Ukraine on February 24.
Under the measure, Norway prohibits aircraft, including drones, operated by Russian nationals or companies "to land on, take off from or fly over Norwegian territory."
The VG newspaper reported that the suspect told the Eastern Finnmark District Court in Vadso that he had been in Norway since August and flew the drones across the country.
Jens Bernhard Herstad, the defense attorney for the Russian national, has said his client acknowledged flying drones across Norway but has not told the court why he is in the country other than as a tourist on vacation.
Justice Minister Emilie Enger Mehl said it was still "too early to draw conclusions." After police review the seized material, charges against the Russian man could be expanded.
Enger Mehl told the broadcaster NRK, "It is known that we have an intelligence threat against us which has been reinforced by what is happening in Europe."
What is the nature of the security threat facing Norway?
As European states seek to reduce reliance on Russian energy sources, Norway has become a key source of natural gas for those countries.
last month, Explosions ripped up two gas pipelines running through the Baltic Sea that had been built to bring Russian gas to Germany. Those blasts occurred in the exclusive economic zones of Denmark and Sweden, just beyond the reach of their territorial waters.
While Russia has not been blamed for the blasts, it has been excluded from partaking in the official investigations being carried out by the Danes and the Swedes.
Since the explosions, security has been heightened around critical infrastructure in Norway and the region. The Norwegian military Home Guard has been called up to protect sensitive sites.
Even before last month's undersea incidents, the Petroleum Safety Authority in Norway had advised energy firms to be alert to the possibility of unwanted drones.
On Thursday, police responded to a threat phoned in against the Nyhamna gas plant, among Europe's largest facilities for exporting energy.