"A total of 23 diplomatic employees of the British Embassy in Moscow are declared personae non gratae and must leave within a week", said the statement, warning that Moscow retained the right to respond if Britain continues to take unfriendly steps against Russian Federation.
Just days after United Kingdom Prime Minister Theresa May said her country would expel 23 Russian diplomats over the nerve agent attack of a Russian ex-spy and his daughter on British soil, Russia is retaliating by expelling Britain's diplomats.
Other measures included closing the British Council and shutting down the British consulate in St Petersburg, while the country indicated it could take further action should there be what it called more "unfriendly" moves.
London has blamed Moscow and on Friday, even directly implicated Putin in the attack, prompting the Kremlin's fury.
Russia's response has also targeted the British Council, which promotes cultural ties.
On Friday, British Foreign Secretary Boris Johnson said it was overwhelmingly likely that Russian President Vladimir Putin himself had made the decision to use a military-grade nerve toxin to strike down Mr Skripal.
MSNBC Host Mocks Trump's New Adviser for Trusting 'God's Will'
Trump on Tuesday dumped via Twitter his secretary of state, former Exxon Mobil CEO Rex Tillerson. Kudlow is joining the administration in the middle of a Cabinet and West Wing overhaul.
The United Kingdom's ambassador to Moscow, Laurie Bristow, was summoned to the Russian ministry on Saturday to be told of Moscow's decision.
The UK government says they were poisoned with a nerve agent of a type developed by Russian Federation called Novichok, and PM Theresa May has said she believes Moscow is "culpable". "Twenty three diplomatic staff at the British embassy in Moscow are declared persona non grata and to be expelled within a week", said a statement.
"We will always do what is necessary to defend ourselves", the ambassador told reporters.
The UK Foreign Office said its priority was looking after its staff in Russian Federation and helping those who will return to Britain.
Britain blames Russian Federation for the nerve-agent attack on Sergei Skripal and his daughter, who were found unconscious in the British city of Salisbury on March 4 and remain in critical condition.
Bristow told reporters afterwards that the crisis had arisen after "the attempted murder of two people using a chemical weapon developed in Russian Federation".
Federer breezes into quarters at Indian Wells, Halep reaches semi-finals
In the victory, Federer won 100 percent of his first serve points and 79 percent of his second serve points. Against Federer, Chardy played a tough first set in windy conditions that persisted throughout the day.
"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."
Russian Federation has complained that Britain has failed to provide any evidence of its involvement in the Salisbury attack and has said it is shocked and bemused by the allegations.
Speaking on Russia-24 television, Zakharova said Britain is taking a tough line against Russia because of frustration at recent advances of Russian-backed Syrian government forces against Western-backed rebels. The pair remain critically ill in the hospital.
British police are trying to reconstruct the movements of former spy Sergei Skripal and his daughter in the crucial hours before they were found unconscious from nerve agent poisoning.
Russian Federation offered some cooperation to British authorities after the 2006 London murder of ex-KGB agent Alexander Litvinenko too. British Prime Minister Theresa May this week ordered 23 Russian diplomats expelled as part of measures to punish Russia over the March 4 poisoning of former spy Sergei Skripal and his daughter Yulia in the city of Salisbury.
Britain said the assistance in that case was not enough, and in 2016, a judge-led inquiry concluded that Putin had probably approved Litvinenko's murder, something Moscow denies.
Evidence points towards Russian Federation on Salisbury attack, says Corbyn
Corbyn's spokesman later told reporters that his record on global crises is bettered by no MP in Parliament. The attack in Salisbury was an appalling act of violence, which we condemn in the strongest terms.