The cyberattack has been ongoing since Monday, said Are Kvistad, a spokesperson for the Norwegian Digitalization Agency (Digdir), the state body in charge of making Norway’s public services more digital and user-friendly, told The Associated Press.

“It’s the biggest attack against Digdir solutions that we have ever experienced,” Kvistad said.

The denial-of-service attacks meant that hackers pushed massive traffic toward the agency in order to block services, including one that enables citizens to use one login across multiple public services.

However, the Digdir spokesman said that the agency managed to keep the services running “practically all the time.”

In a Telegram post on Wednesday widely reported by Norwegian media, the pro-Russian hacker group Server Killers claimed responsibility for the attack and said it had declared cyber war on Norway after the country renewed its security cooperation with Ukraine on Aug. 23.

On Sunday, Norwegian Prime Minister Jonas Gahr Støre announced during a visit to Kyiv that Norway would provide 85 billion Norwegian crowns (9.2 billion US dollars) to Ukraine from next year’s state budget for a third year in a row.

The two countries also committed to further cooperation when it comes to drone technology and other forms of modern warfare.

Norwegian officials did not comment on the hackers’ claim by publication time.

All countries in Europe are on high alert with Russia stepping up its sabotage and malign activity across the continent since Moscow’s full-scale invasion of Ukraine in February 2022. Officials say the attacks are intended to undermine support for Ukraine, spread fear and discord in European societies and drain investigative resources.

In 2025, Norwegian authorities said Russian hackers were likely behind suspected sabotage at a dam in the country. During that incident, hackers gained access to a digital system which remotely controls one of the dam’s valves and opened it to increase the water flow. A three-minute long video showing the dam’s control panel and a mark identifying a pro-Russian cybercriminal group was published on Telegram at the time, the police said.

Last year, Danish authorities blamed Russia for carrying out cyberattacks against infrastructure and websites in Denmark in 2024 and 2025. Danish officials said pro-Russian group Z-Pentest carried out a “destructive attack” on the water utility company in 2024 and that a separate group, NoName057(16), was responsible for a cyberattack on Danish websites ahead of the 2025 local elections. Voth have links to the Russian state, they said.

According to Norwegian media, Server Killers were linked directly or indirectly to previous cyberattacks in Norway and other European countries.