Britain on Wednesday ordered the expulsion of 23 Russian diplomats in retaliation for the poisoning of a former Russian spy on U.K. territory earlier this month.
U.K. premier Theresa May told parliament the individuals had a week to leave the country — an echo of Cold War tensions with the then Soviet Union.
A scandal has gripped British-Russian relations since 66-year-old Sergei Skripal, alongside his 33-year-old daughter, was poisoned with a suspected nerve agent in Salisbury, England.
The British authorities had demanded an explanation by Moscow but claimed none was forthcoming.
Russia has dismissed British claims of foul play as “hysteria”.
In November 2006 a Russian intelligence defector called Alexander Litvinenko was fatally poisoned with a radioactive substance in London, straining ties between London and Moscow.