All in all, on Monday, about 100 Russian diplomats were expelled from 16 European countries, as well as US, Canada and Australia.
North Atlantic Treaty Organisation is the latest entity punishing Russia for its alleged role in a nerve agent attack on former Russian spy Sergei Skripal on British soil.
A number of countries including the United States said the Russian diplomats they were throwing out were actually undeclared spies.
US General Jim "Mad Dog" Mattis has delivered a strong message to Moscow over the poisoning of ex-Russian intelligence officer Sergei Skripal and his daughter.
In an unprecedented act of coordination, at least 24 countries have echoed Britain's action in response to the March 4 attack on Skripal and his daughter in the English city of Salisbury. Numerous countries to follow suit on Monday said they did so out of solidarity with the British government.
Moscow has fiercely denied any involvement in his attempted murder, instead pointing the finger at London. Foreign Minister Sergei Lavrov said the US had used "colossal pressure and colossal blackmail" to get other entities to act against Russian Federation.
Lavrov said the coordinated response was the result of "colossal pressure, colossal blackmail" from the United States. Moscow has promised retaliation for the diplomatic expulsions.
"Relations between Russian Federation and the West are entering a period of full Cold War", foreign policy analyst Fyodor Lukyanov wrote in the Vedomosti daily.
But Western officials made it clear in announcing the expulsions that they share Britain's assessment that only the Kremlin could have been responsible.
Applauding the expulsions, White House Press Secretary Sarah Huckabee Sanders told reporters, "We are certainly applying pressure on Russian Federation, we're certainly encouraging working with our allies and partners also to do so, and I think you've seen an unprecedented number of countries and join the United States in that effort". More than 130 people are suspected of having been exposed to the nerve agent used in the attack, a military-grade chemical weapon known as Novichok, which was developed in the Soviet Union in the 1970s.