NATO also denied accreditation to three more diplomats from Russia's mission to the alliance.
NATO expels seven Russian diplomats in response to UK nerve agent attack
NATO expelled seven Russian diplomats on Tuesday, adding to the global condemnation of the suspected poisoning of a former Russian spy in Britain.
The military alliance's chief Jens Stoltenberg said on Tuesday that the expulsions "will send a clear message to Russia that there are costs and consequences for their unacceptable pattern of behaviour."
NATO has also denied accreditation to three more Russian diplomats, bringing the total number of positions available down from 30 to 20.
Pressure on Moscow is mounting as Australia's Prime Minister Malcolm Turnbull announced the expulsion of two Russian diplomats from his country earlier on Tuesday.
Governments across the West have joined together in punishing the Kremlin. Over 100 Russian diplomats have been removed, the biggest western expulsion of Russian diplomats since the height of the Cold War.
"Together with the United Kingdom and other allies and partners, Australia is taking action in response to the recent nerve agent attack in Salisbury, UK," Mr Turnbull said.
"Two Russian diplomats identified as undeclared intelligence officers will be expelled by the Australian government for actions inconsistent with their status, pursuant to the Vienna Conventions."
Foreign Minister Julie Bishop said other options over the poisoning incident, such as Australia boycotting the 2018 World Cup in Russia, could also be taken.
"There are a whole range of further options of action that could be taken, the boycott of the World Cup is one that could be taken in relation to this matter," Ms Bishop said in Canberra.
The Russian embassy in Canberra accused Australia of blindly following Britain, adding that the decision jeopardised the bilateral relationship.
"It is astonishing how easily the allies of Great Britain follow it blindly contrary to the norms of civilised bilateral dialogue and international relations, and against … common sense," said the embassy.