Russia will expel 23 British diplomats as tensions escalate during the spy poisoning stand-off.
The move comes after Theresa May expelled 23 Russian diplomats from the UK who she said were 'undeclared intelligence officers' earlier this week.
Moscow had failed to respond to a deadline set by the Prime Minister to explain how the nerve agent that poisoned former Russian spy Sergei Skripal and his daughter Yulia found its way into Britain.
The pair were found unconscious on a bench outside a shopping centre in Salisbury on Mar. 4.
They were poisoned by a deadly nerve agent called Novichok and remain critically ill in hospital.
NHS England said Detective Sergeant Nick Bailey, the police officer exposed to the substance while helping the Skripals, is no longer in a critical condition.
Now Moscow has said the British diplomats must leave within a week - mirroring Theresa May, who gave Russian diplomats the same order.
This article has been adapted from its original source.
© Associated Newspapers Ltd.