Russia's UN ambassador on Monday called the US decision to expel 12 diplomats working at the Russian mission to the United Nations a "very unfortunate and very unfriendly move."
Vassily Nebenzia told reporters that the 12 diplomats will have to leave by April 2, although the Russian government will protest the US decision that comes amid a British-Russian row over the nerve gas attack on an ex-spy.
The United States informed the United Nations on Monday of the expulsions, invoking a 1947 US-UN agreement that allows such action for "abuse of privileges of residence."
The United States ordered 60 Russians to leave in a coordinated move that also saw European Union countries, Canada, Ukraine and Albania expelling scores more.
US Ambassador Nikki Haley told reporters that Russia was "increasingly" showing "bad judgment".
"When you see these espionage tactics that are taking place right here at the heart of the UN, we can't have that," she said.
"Unfortunately, Russia is now being held accountable for a lot of things and they have a decision to make."
Nebenzia declined to give details of the 12 diplomats who are among a staff of about 95 who work at the mission.
UN spokesman Farhan Haq confirmed that the United States had informed the United Nations of the decision under the US-UN agreement.
"Given the sensitivity of the matter, which is ongoing, we will not comment further at this stage other than to confirm that the secretary-general will closely follow this matter and engage as appropriate with the governments concerned," said Haq.
President Donald Trump also ordered the closure of the Russian consulate general in Seattle.
"Here in New York, Russia uses the United Nations as a safe haven for dangerous activities within our own borders," Haley said earlier in a statement announcing the expulsions from the Russian mission.
Britain had urged allies to take strong action in response to the March 4 attack in England that left former Russian spy Sergei Skripal and his daughter in critical condition.