An incident that could take on tragic proportions has been revealed by Norway‘s intelligence service (PST), which said Russian hackers took control of a dam.

The hackers even opened a gate and let the water flow for four hours.

It is the first time Oslo has blamed Moscow for last April’s cyberattack in Bremerhaven in western Norway.

The attack on the hydroelectric power generation dam released 500 liters of water per second for four hours until it was detected and stopped.

“The goal of this type of operation is to influence and cause fear and chaos in the general population. Our Russian neighbor has become more dangerous,” the PST chief said.

The incident, as reported by the Guardian, caused no injuries or damage, as the water level of the river and dam was well below flood stage.

The alleged perpetrators reportedly posted a three-minute video on Telegram on the day of the attack, watermarked with the name of a pro-Russian cybercriminal group.

The intelligence services of Norway, which generates most of its electricity from hydroelectric dams, had previously warned of the potential danger of such attacks on energy infrastructure.