Twenty-five European countries, Australia, Canada and the US have announced that they will be expelling 123 Russian diplomats over the coming week.
Days later Russia responded in kind, expelling an equal number of diplomats from those countries, except Belgium, Hungary, Georgia and Montenegro. It also announced that the UK diplomatic mission to Moscow will have to cut staff by another 50 diplomats.
Last week, the UK expelled 23 Russian officials. In addition, Bulgaria and Luxemburg recalled their ambassadors from Moscow for consultations.
NATO also expelled seven diplomats from Russia's mission to the alliance.
Earlier in March, UK's Prime Minister Theresa May accused Russia of being behind the attack on former Russian spy Sergei Skripal and his daughter Yulia.
The two were found unconscious on a bench near a shopping centre in the English town of Salisbury on March 4.
The UK government has claimed that a Russian-made nerve agent was used to poison the two. Russia has denied the accusations and last week expelled 23 UK diplomats.
In response, on Friday, heads of European Union countries held a special meeting to decide on measures they can take in support of the UK, which is currently in the process of leaving the union. NATO allies - US and Canada - also decided to take action in solidarity with London.
Here is a breakdown of the number of Russian diplomats each country has vouched to expel.
European Union member states:
France - 4
Poland - 4
Germany - 4
Lithuania - 3
Czech Republic - 3
Denmark - 2
Italy - 2
Spain - 2
Netherlands - 2
Estonia - 1
Latvia - 1
Sweden - 1
Belgium - 1
Finland - 1
Romania - 1
Croatia - 1
Hungary - 1
Ireland - 1
Total: 35
Non-EU European states:
Ukraine - 13
Moldova - 3
Albania - 2
Norway - 1
Macedonia - 1
Georgia - 1
Montenegro - 1
Total: 22
Other countries:
US - 60
Canada - 4
Australia - 2
Total: 66
NATO:
NATO - 7
