The EU's foreign policy chief Josep Borrell on Friday accused Russian organisations of trying to hack European politicians and spread disinformation.
"Some EU Member States have observed malicious cyber activities, collectively designated as Ghostwriter, and associated these with the Russian state," Borrell said in a statement.
"Such activities are unacceptable as they seek to threaten our integrity and security, democratic values and principles and the core functioning of our democracies."
Borrel said that the cyberattacks had targeted "numerous members of Parliaments, government officials, politicians" as well as reporters and citizens in the EU.
"These activities are contrary to the norms of responsible state behaviour in cyberspace as endorsed by all UN Member States," the statement continued.
He flagged that malicious cyber activities had been observed in several member states and linked to the hacker outfit called "Ghostwriter". Germany said the outfit, which is associated with the Russian state, has tried to steal data from MPs and spread online disinformation.