But Stoltenberg, who said earlier this month he did not want a new Cold War with Moscow, said the alliance planned to continue its "dual-track approach of strong defence and openness to dialogue" with Russian Federation.
US officials announced that 48 "intelligence officers" attached to Russian diplomatic missions in the United States would be expelled, along with 12 accredited to the United Nations in NY.
NATO Secretary General Jens Stoltenberg said in a statement that the intensive consultations have taken place among NATO allies following the "attack in Salisbury" against Skripal and his daughter.
"I actually think that Russian Federation has underestimated the unity of North Atlantic Treaty Organisation allies", he said.
European Union member Ireland and Moldova on Tuesday joined the list of those countries expelling Russian diplomats over the Skripal poisoning.
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Ireland also announced it was ordering one Russian diplomat to leave.
Downing Street saying that more than 115 Russian diplomats had been ordered home by friends and allies, Dublin added one more to the list.
Irish deputy premier and foreign minister Simon Coveney said: "The use of chemical weapons, including the use of any toxic chemicals as weapons, by anyone, anywhere, is particularly shocking and abhorrent".
Russian Foreign Minister Sergei Lavrov accused Washington of applying "colossal" pressure on allies to expel its diplomats, and vowed to respond to the move.
In retaliation, Moscow expelled an equal number of British diplomats and closed a British consular mission.
The Prime Minister added: "It is also important to note that our partners are not only taking these measures out of solidarity with the United Kingdom, but also because they recognise the threat that these Russian networks pose to the security of their own countries and the pattern of Russian aggression which has affected us all".
Kremlin spokesman Dmitry Peskov said Moscow regrets these moves of the Western countries, and Russia's diplomatic authorities will analyze the situation and propose response measures to President Vladimir Putin for his final decision.