The European Union has threatened sanctions on Russia over "unacceptable" cyber attacks and espionage.
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.
The hackers had attempted to access computer systems and personal accounts in the bloc, and steal data, he added.
"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.
Germany's foreign ministry has accused the Russian military intelligence service GRU of carrying out phishing attacks to try and influence the country's parliamentary elections. Moscow has not responded to the allegations.
Berlin has opened an investigation "on suspicion of foreign intelligence activity".
"The European Union and its Member States strongly denounce these malicious cyber activities, which all involved must put to an end immediately," said Borrell, threatening sanctions.
"We urge the Russian Federation to adhere to the norms of responsible state behaviour in cyberspace."
"The European Union will revert to this issue in upcoming meetings and consider taking further steps."