Russian hackers took control of a Norwegian dam this year, opening a floodgate and allowing water to flow unnoticed for four hours, Norway’s intelligence service has said.
The admission, by the Norwegian Police Security Service (PST), marks the first time that Oslo has formally attributed the cyber-attack in April on Bremanger, western Norway, to Moscow.
The attack on the dam, which which is used for farming fish, released 500 litres (132 gallons) of water a second for four hours until the incident was detected and stopped.
The head of PST, Beate Gangås, said on Wednesday: “Over the past year, we have seen a change in activity from pro-Russian cyber actors.” The Bremanger incident was an example of such an attack, she added.
“The aim of this type of operation is to influence and to cause fear and chaos among the general population. Our Russian neighbour has become more dangerous.”
The incident did not cause any injuries or damage because the water level of the river and the dam, which is close to the town of Svelgen, was a long way below flood capacity.
The alleged perpetrators reportedly published a three-minute video, watermarked with the name of a pro-Russian cybercriminal group, on Telegram on the day of the attack.
Kripos, Norway’s organised crime police unit, told the Aftenposten newspaper it was “aware this group brought together several actors who commit crime in the cyber domain” and had been linked to several cyber-attacks against businesses in the west in recent years.
Gangås said: “Russian intelligence services spend significant resources identifying, cultivating and recruiting contacts in Norway. Norwegian citizens could be good sources of information for them.”
Intelligence services in Norway, which produces the majority of its electricity using hydropower dams, had previously warned of the potential risk of such attacks on energy infrastructure.
Norway and Russia share a 123-mile (198km) border, with a crossing at Storskog, Europe’s only open Schengen border with Russia.
The Russian embassy in Oslo said Gangås’s statements were “unfounded and politically motivated”.
It told Reuters news agency: “It is obvious that the PST is unsuccessfully trying to substantiate the mythical threat of Russian sabotage against Norwegian infrastructure this year, which it itself invented in its February (annual) report.”
Last year, Richard Moore, the head of Britain’s Secret Intelligence Service, MI6, accused Russia of a “staggeringly reckless campaign” of sabotage in Europe, in part to frighten countries from helping Ukraine. Moscow denies the allegation.
The PST has been contacted for comment.
This article was amended on 15 August 2025. An earlier version said that the cyber-attack was on an electricity-producing hydropower dam. In fact, this dam is used for fish farming.
