The leaders of France, Germany, the United States, and Britain say Russian responsibility is the "only plausible explanation" for the poisoning of a former spy with a military-grade nerve agent in England 11 days ago.
The foreign office said that Britain's National Security Council will meet to discuss further actions against Russian Federation.
They called on Russian Federation to provide a complete disclosure of the Novichok programme to the Organisation for the Prohibition of Chemical Weapons (OPCW) in The Hague.
"Novichok, which is a military grade nerve agent, can not be manufactured by a non-state sponsor".
The country's Ministry of Foreign Affairs announced it had ordered the diplomats to leave within a week, moments after Britain's ambassador to Russia Laurie Bristow left the ministry in Moscow.
Britain also said it would invest 48 million pounds ($67 million) in a new chemical warfare defence centre at its Porton Down military research laboratory, where scientists identified the nerve agent used against Skripal.
"The United States believes that Russian Federation is responsible for the attack on two people in the United Kingdom, using a military-grade nerve agent", US Ambassador Nikki Haley told an emergency council meeting.
Accusations have been growing against Moscow over the March 4 attack, in which former Russian spy Sergei Skripal and his 33-year-old daughter were targeted by a nerve agent in a British shopping district.
Both father and daughter were found unconscious on a bench at a Salisbury beach, about 145 kilometers away from London.
The leaders described the poisoning as "the first offensive use of a nerve agent in Europe since the Second World War", adding that Russia's actions "threaten the security of us all".More news: Crack in Florida bridge deemed no concern just hours before collapse
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Britain announced Wednesday it will expel nearly two dozen Russian diplomats, sever high-level bilateral contacts with Moscow and take both open and covert action against Kremlin meddling after the poisoning of a former spy.
Zakharova further accused Britain of refusing to "grant access to Russian citizen (Yulia) Skripal" or to work with Moscow through the OPCW and give Russia access to the poisonous substance.
Kosachev says "I believe sooner or later we will learn the truth and this truth will be definitely very unpleasant for the Prime Minister of the United Kingdom" and others who he says "have absolutely blindly supported this theory of Russian involvement". "It threatens the security of us all", the USA and European leaders said.
"I decided not to go to the official Russian Federation stall.in solidarity with our British friends", he told reporters, adding Paris was in contact with London to decide on "appropriate answers to this aggression on the soil of our British allies".
However, those measures have not been confirmed, nor is it known whether that will come before Sunday's presidential election, which Vladimir Putin is expected to retain his seat.
Russian Federation today retaliated, announcing it will remove British diplomats from its ranks and the British position was irresponsible.
Russian Federation has complained that it has had no access to nerve agent to be able to analyse it.
"Our priority today is looking after our staff in Russian Federation and assisting those that will return to the United Kingdom", it said in a statement. He was freed in 2010 as part of an exchange of spies with the United States, and eventually settled in Britain.
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.