Britain, which shied away from tough action after a previous Russian political assassination on its soil, on Wednesday announced a more robust response, including the expulsion of 23 suspected Russian spies.
Czech Foreign Minister Martin Stropnicky on Saturday denied Moscow's accusation that the nerve toxin used against a former Russian double agent and his daughter in southern England came from the Czech Republic.
The tensions come as presidential elections take place in Russian Federation.
"They are using everything: schools, kindergartens, hospitals - the battle for the turnout is unprecedented", said Roizman, one of the rare opposition politicians to hold a significant elected office.
It further said, "Twenty-three diplomats of the British Embassy in Moscow have been declared personae non gratae and will be expelled within a week's time".
A statement by the Russian Foreign Ministry said it will close the British Council, an organization for cultural education and educational opportunities.
The British Council, the UK's worldwide organisation for cultural relations and educational opportunities, said it was "profoundly disappointed" at being told to cease operations in Russian Federation.
Former Royal Navy chief of staff Lord West said the world needs to "get a grip and make some sensible moves".
"The British side is warned that in case of further unfriendly actions against Russia, the Russian side reserves the right to take further retaliatory measures", according to the statement.
"The measures are more harsh, but the British deserved them".
Saudi Arabia will have nuclear bomb if Iran does
Iran insists that based on the International Atomic Energy Agency's NPT, it is entitled to pursue its peaceful nuclear program. Saudi Arabia will work to build its own nuclear weapons if Iran acquires them, according to the kingdom's heir apparent.
Czech Foreign Minister Martin Stropnicky said this was "wholly unsubstantiated" and "highly speculative".
True, the primary target of the London attack with the banned Soviet-developed binary chemical weapon was Sergei Skripal, an ex-Russian spy, who was working for the British intelligence. Eight months after that attack, Britain finally expelled four Russian diplomats; but a full inquest, which concluded Putin was probably responsible for the killing, was not completed for nine years.
Skripal had taken his daughter, who was on a visit from Moscow, out for lunch in Salisbury before they both collapsed on a bench.
Russian Federation insists it had no motive to target Skripal with what Britain says was a highly potent Soviet-designed nerve agent called Novichok, in the first such attack in Europe since World War II.
Putin has barely weighed in on the row, telling a BBC reporter this week: "Sort things out from your side and then we will discuss this with you".
Speaking at the same event in Dubai, Tory former chancellor George Osborne, attacked Labour leader Jeremy Corbyn's response.
The UK foreign secretary will meet his European Union counterparts and Nato Secretary General Jens Stoltenberg for talks in Brussels on Monday.
Skripal's poisoning has prompted police in Britain to re-examine the cases of several Russians who have died or fallen ill on United Kingdom soil, amid criticism that the British government shut down the original investigations for political reasons without getting to the bottom of what happened.
Most recently - on Monday - Nikolai Glushkov, a known and high-profile Putin critic and associate of Boris Berezovsky, was found dead in his London home.
His latest attack, in a hard-hitting article in the Sun on Sunday, comes after he accused Mr Putin of personally masterminding the Salisbury poisoning.