The EU's diplomatic chief Federica Mogherini held crisis talks with the bloc's ambassador to Moscow Sunday after he was recalled over the poisoning of a former Russian spy in England.
EU leaders summoned envoy Markus Ederer back to Brussels for consultations as international pressure builds on Moscow over the attempted assassination of Sergei Skripal and his daughter Yulia in the British city of Salisbury.
At a summit on Friday, the bloc unanimously backed Britain's assessment that the Kremlin was to blame for the incident -- the first offensive use of a nerve agent in Europe since World War 2.
In a brief statement on Sunday, Mogherini's office said she had held "consultations with the Head of European Union Delegation in the Russian Federation".
No further details were given beyond saying Ederer would "continue institutional consultations in the coming days".
A number of European countries are expected to take further steps to punish Moscow on Monday, with the Czech Republic, Lithuania, Denmark and Ireland considering expelling Russian diplomats.
German Chancellor Angela Merkel said on Friday that further coordinated actions were "necessary" to respond to the attack, while French officials have said Paris too was ready to act.
Britain and Russia have expelled 23 of each other's diplomats in tit-for-tat exchanges, while Moscow has also shut down the operations of the British Council cultural organisation in its territory.
Moscow denies any involvement in the attack on the Skripals and has accused Britain of orchestrating a campaign against it.
On Saturday the BBC reported that Skripal had written to Russian President Vladimir Putin several years ago asking for a pardon for selling secrets to British intelligence.
Skripal, 66, and his 33-year-old daughter are both in a coma after being poisoned with a nerve agent -- identified as the Soviet-made "Novichok" by the British government -- on March 4.