Moscow is also considering its response to the United States after Donald Trump's administration imposed sanctions on Russians allegedly involved in interfering with the 2016 U.S. elections and cyber-attacks.
Asked on Friday whether Moscow would expel United Kingdom diplomats, Russia's foreign minister Sergei Lavrov said: "Of course we will".
The remarks implicating the Russian president directly are likely to escalate the dispute between London and Moscow.
'Who to vote for, how to exercise your right to free choice, that is the decision of each person, ' the 65-year-old said in a video released late Thursday and carried in news bulletins Friday morning.More news: President Donald Trump Compares Mexican Immigrants to 'Professional Mountain Climbers'
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The sanctions prompted a swift threat of retaliation from the Russian government.
Boris Johnson has taken the war of words with Russian Federation one step further by suggesting that Vladimir Putin was personally involved in the attack on ex-spy Sergei Skripal. President Donald Trump and the leaders of France and Germany joined British Prime Minister Theresa May on Thursday to directly pin blame for the attack on Russian Federation. Their joint statement said there was "no plausible alternative explanation" to Russian Federation being to blame for the attack.
British Foreign Secretary Boris Johnson speaks to media during a visit to a Battle of Britain bunker in Uxbridge on 16 March 2018.
The source of the nerve agent used - which Britain says is Soviet-made Novichok - is unclear.
As Palmer reports, Russia's ongoing denials and indignation do not bode well for prospects of ever getting to the truth about the attack in southwest England, which has left both of the Skripals and a police officer hospitalized.