Russia is to expel 23 British diplomats amid tensions over the nerve agent attack on a former spy and his daughter in the UK.
The Russian foreign ministry said staff from the UK’s Moscow embassy would be expelled within a week.
It also said it would close the British Council in Russia, which promotes cultural ties between the nations, and the British Consulate in St Petersburg.
The move comes in response to Britain’s decision to expel 23 Russian diplomats.
They were ordered to leave over the incident on 4 March which the UK government has blamed on Russia – but which Russia denies.
Russian ex-spy Sergei Skripal, 66, and his daughter Yulia Skripal, 33, remain critically ill in hospital, after they were found unconscious on a bench in Salisbury, Wiltshire.
The UK government says they were poisoned with a nerve agent of a type developed by Russia called Novichok, and PM Theresa May has said she believes Moscow is “culpable”.
On Friday, Foreign Secretary Boris Johnson said it was “overwhelmingly likely” that Russian President Vladimir Putin had ordered the nerve agent attack.
Britain’s ambassador to Russia, Laurie Bristow, was summoned to Russia’s foreign ministry on Saturday and was handed Russia’s response to the UK’s sanctions.
The foreign ministry, in a statement, said that the British diplomats would be “declared persona non grata”, adding that it “reserves the right to introduce other retaliatory measures in case of further unfriendly actions”.
Mr Bristow, after leaving the meeting, said that the UK had no quarrel with the Russian people and would “always do what is necessary to defend ourselves”.