“The malicious cyber campaign shows Russia’s continuous pattern of irresponsible behaviour in cyberspace, by targeting democratic institutions, government entities and critical infrastructure providers across the European Union and beyond,” Josep Borrell, the bloc’s foreign policy chief, said in a statement on Friday on behalf of the 27 member states.

“The EU will not tolerate such malicious behaviour, particularly activities that aim to degrade our critical infrastructure, weaken societal cohesion and influence democratic processes,” he added, referring to the June elections to the European Parliament.

Using similarly critical language, NATO called on Moscow to abide by its “international obligations” and stressed the alliance would “employ the necessary capabilities in order to deter, defend against and counter the full spectrum of cyber threats.”

Both put the blame on APT28, an acronym for Advanced Persistent Threat Actor 28, a cyber espionage group linked to Russia’s military intelligence service (GRU).

In Germany, APT28 is accused of compromising e-mail accounts of members of the Social Democratic Party (SPD), the leading force in the ruling coalition. Berlin has already summoned the acting chargé d’affaires of the Russian embassy.

“This is absolutely intolerable and unacceptable and will have consequences,” said Germany’s Foreign Minister Annalena Baerbock.

In the Czech Republic, the group is said to have targetted some state institutions by exploiting a “previously unknown vulnerability in Microsoft Outlook,” the country’s foreign affairs ministry said on Friday. The interference began in 2023, it noted.

The publishing of findings by the two countries prompted the denouncing statements by the EU and NATO, which were released almost simultaneously.

The news comes amid a high-alert atmosphere in Eastern and Nothern Europe over the dangers posed by Russian hybrid warfare.

In recent days, Estonia, Latvia, Lithuania, Sweden and Finland have sounded the alarm about the jamming of GPS signals, which forced Finnish airline Finnair to suspend services to Tartu, a city in Estonia. The phenomenon is seen as a new attempt by the Kremlin to retaliate against sanctions imposed over the invasion of Ukraine.

“These incidents are part of an intensifying campaign of activities which Russia continues to carry out across the Euro-Atlantic area, including on Alliance territory and through proxies,” NATO said on Thursday. “This includes sabotage, acts of violence, cyber and electronic interference, disinformation campaigns, and other hybrid operations.”