Russia announced on Saturday it would expel 23 British diplomats and halt the activities of the British Council in response to London's measures over the poisoning of a former Russian double agent and his daughter.
"Twenty three diplomatic staff at the British embassy in Moscow are declared persona non grata and are to be expelled within a week," the foreign ministry said in a statement after summoning British ambassador Laurie Bristow.
Moscow said the move was a response to Britain's "provocative actions" and "baseless accusations over the incident in Salisbury on March 4," referring to the poisoning of Sergei and Yulia Skripal with a nerve agent developed in the Soviet Union, which Britain has blamed on Russia.
Russia also said it was halting the activities of the British Council, Britain's international organisation for cultural relations and educational opportunities, across the country.
"Due to the unregulated status of the British Council in Russia, its activity is halted," the foreign ministry said.
And the ministry had also warned Britain that "if further unfriendly actions are taken towards Russia, the Russian side retains the right to take other answering measures."
Britain said that it "anticipated a response of this kind" and officials would meet next week to consider the next steps.
“Russia’s response doesn’t change the facts of the matter - the attempted assassination of two people on British soil, for which there is no alternative conclusion other than that the Russian State was culpable," the UK's foreign office said in a statement.
The foreign secretary Boris Johnson said on Friday it was "overwhelmingly likely" that Vladimir Putin directed the use of the nerve agent on Britain's streets.
The Foreign Secretary's comments prompted a rebuke form Mr Putin's spokesman Dmitry Peskov. He said: "Any reference or mentioning of our president is nothing else but shocking and unpardonable diplomatic misconduct."
Moscow’s response to the expulsions came after UK police announced they were treating the death of another Russian exile as murder.
Nikolai Glushkov was found dead at his south London home on Monday, eight days after the attack on Mr Skripal. He died from ‘compression to the neck’, according to police. Mr Glushkov was a close friend of Vladimir Putin’s arch-enemy Boris Berezovsky who died in exile in 2013 at his mansion near London.
Detectives said that there was nothing to suggest a link between Mr Glushkov's death and that of Mr Skripal and there was no suggestion that he was poisoned.
Police have started to contact other Russian exiles to discuss their safety following a reassessment by security services, according to the BBC.