The EU has imposed sanctions on six senior Russian officials and a chemical research centre over the Novichok poisoning of anti-Putin campaigner Alexei Navalny.
Those targeted by EU travel bans and asset freezes include Federal Security Service (FSB) chief Alexander Bortnikov and two deputy defence ministers.
Mr Navalny is recovering in Berlin. He has blamed President Vladimir Putin for the nerve agent attack in August.
The Kremlin has denied any role in it.
EU foreign ministers agreed on the sanctions on Monday, urged on by France and Germany, who are convinced the nerve agent came from a state facility.
The EU statement on Thursday says that "taking into account that Alexei Navalny was under surveillance at the time of his poisoning, it is reasonable to conclude that the poisoning was only possible with the involvement of the Federal Security Service".
The Russian government disputes the finding by European experts that the extremely toxic chemical weapon Novichok, developed by Soviet scientists in the Cold War, was used.
The EU statement however says the sanctions are part of action to counter "the proliferation and use of chemical weapons". EU leaders are meeting for a two-day summit in Brussels.