The Russian government expelled 23 British diplomats Saturday in response to Great Britain's decision to expel Russian operatives over the poisoning of a former Russian double agent and his daughter in England.
After three days of threats that Russia's response was coming, Moscow announced on Saturday that it expel 23 diplomats, close the British Consulate-General in St Petersburg and close the British Council in Moscow.
British police said there is no apparent link between the attack on Glushkov and the poisoning of the Skripals, but both have raised alarm in the West at a time when Russian Federation is increasingly assertive on the global stage and facing investigations over alleged interference in the Donald Trump's election as US president.
The Foreign Ministry said Moscow's measures were a response to what it called Britain's "provocative actions and unsubstantiated accusations".
British Prime Minister Theresa May announced the decision earlier this week to expel the Russian diplomats, who she said were spies for the Russian government.
Tensions between the two nations have increased dramatically since the March 4 nerve-agent attack on Sergei Skripal, 66, and his 33-year-old daughter Yulia in Salisbury. The Skripals remain in critical condition.
The Kremlin has denied involvement, and Russia's ambassador to Europe has now suggested the nerve toxin could have come from Britain's own military research facility at Porton Down, noting it is not far from Salisbury.
"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.
"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", it said in a statement.
Russian Federation was "in flagrant breach of worldwide law", she told her Conservative Party's spring forum, adding that Britain "will consider our next steps in the coming days".
The UK government was backed this week by allies France, Germany and the United States in its assessment that there was "no plausible alternative explanation" than that Russian Federation was responsible for the nerve agent attack.
The confrontation escalated after May accused Moscow on Wednesday of an "unlawful use of force" involving a weapons-grade nerve agent and ordered out the largest number of Russian diplomats from London in 30 years.
"We have evidence that Russian Federation has been investigating delivery of nerve agents and has been creating and stockpiling Novichok", British Foreign Secretary Boris Johnson said, according to the paper.
"We have said on different levels and occasions that Russian Federation has nothing to do with this story", he said.
Russian Federation has demanded that Britain share samples collected by investigators.
In a dramatic twist Friday, London's Metropolitan Police said that the death of Russian businessman Nikolai Glushkov, who was found dead Monday in his London home, was now being treated as murder. An autopsy showed he died from "compression to the neck", the police said in a statement, adding that there was no evidence he had been poisoned or to link his death to the attack on the Skripals.
Yulia and Sergei Skripal. In 2008, Russian Federation ordered the council to close all its offices except the Moscow headquarters as part of retaliation for the UK's expulsion of diplomats over the radioactive poisoning of former security-service officer Alexander Litvinenko in 2006. He was granted refuge in the UK after a high-profile spy exchange between the United States and Russian Federation in 2010.