Russian-linked hackers carried out cyberattacks against Danish infrastructure and government-related websites in 2024 and 2025, Danish authorities said in a newly published assessment. The report revealed several incidents that officials had not disclosed earlier.

Denmark’s Defence Intelligence Service said on Thursday that Moscow was responsible for what it called “destructive and disruptive” cyber operations.

Water utility and election websites targeted

According to the assessment, one major attack hit a Danish water utility in 2024. In addition, hackers launched a wave of denial-of-service attacks that shut down several Danish websites just before regional and local elections held last month.

The affected water company said the cyber intrusion caused pipes to burst. As a result, some homes temporarily lost access to water.

Local official warns against weak digital security

Jan Hansen, head of the Tureby Alkestrup Waterworks near Copenhagen, said the incident highlighted the dangers of cutting corners on cybersecurity. He urged other companies not to reduce spending on digital protection and to make sure they have cyber insurance.

Hansen explained that the breach happened after the waterworks switched to a cheaper cybersecurity system. That system turned out to be weaker than the one it replaced.

Part of Russia’s wider hybrid warfare strategy

Meanwhile, Denmark’s intelligence service said the attacks were part of Russia’s broader “hybrid warfare” campaign against Western countries. The goal, it said, is to create instability and punish nations that support Ukraine.

Russian hackers have faced similar accusations elsewhere in Europe. In one earlier case, hackers targeted a Norwegian dam. Authorities said the attackers opened valves and allowed water to spill out.

Danish minister raises alarm over preparedness

Torsten Schack Pedersen, Denmark’s minister of resilience and preparedness, said the attacks caused limited physical damage. However, he warned of serious long-term consequences.

“It shows that there are forces capable of shutting down important parts of our society," he said during a news conference Thursday, as reported by Danish broadcaster DR.

Pedersen added that the incidents showed Denmark was not fully prepared to deal with such threats, DR reported.

Part of a broader pattern across Europe

The Danish cases are among a growing number of incidents that Western officials believe are linked to a coordinated Russian campaign across Europe. An Associated Press database has recorded 147 such incidents so far, including the two attacks disclosed by Denmark this week.

Officials noted that not all cases become public immediately. In many situations, it can take months to confirm a link to Moscow.

They said the campaign began after President Vladimir Putin launched Russia’s full-scale invasion of Ukraine in 2022. While the effort aims to weaken support for Kyiv, officials also believe Russia is testing Europe’s vulnerabilities and stretching law enforcement resources.

Pro-Russian hacker groups named

The Danish intelligence agency identified two groups behind the attacks. It said a pro-Russian group called Z-Pentest carried out the “destructive attack” on the water utility in 2024.

Another group, NoName057(16), was blamed for the cyberattacks on Danish websites ahead of the recent elections. Authorities said both groups have ties to the Russian state.

“The Russian state uses both groups as instruments of its hybrid war against the West. The aim is to create insecurity in the targeted countries and to punish those that support Ukraine,” the statement said.

According to DR, NoName057(16) acted in November to disrupt the elections.

Impact on local communities

The Tureby Alkestrup Waterworks supplies water to several villages about 35 kilometers south of Copenhagen. The utility said hackers altered water pressure, which caused a pipe to rupture.

As a result, about 50 households were left without water for roughly seven hours. Around 450 homes experienced a water outage lasting about one hour.

Germany also raises concerns over Russia

Elsewhere in Europe, Germany has taken diplomatic action over similar concerns. On December 12, German authorities summoned Russia’s ambassador in Berlin.

The move followed accusations by Germany’s foreign ministry that Moscow was behind acts of sabotage, cyberattacks, and election interference.

These allegations included a 2024 cyberattack on German air traffic control, according to German Foreign Ministry spokesperson Martin Giese.