She said it was "unfortunate" she had to criticise Vladimir Putin but added the “dire situation” in Ukraine demanded “clear and strong condemnation of Russian actions”.
“The crisis is spreading, endangering many more,” Ms Haley said, as she called for the Minsk peace agreement to be implemented “immediately”.
During a phone conversation between Mr Trump and his Russian counterpart at the weekend, both men agreed to work as partners on a variety of issues from Ukraine to Iran and violence in the Middle East.
And Ms Haley’s critical comments will surprise some observers as the billionaire property tycoon repeatedly called for closer ties with Russia during his election campaign.
Earlier this month he said only “stupid people” would oppose the US forging a new bond with the Kremlin.
The UN envoy’s comments came as influential Republican senator John McCain warned America’s commander-in-chief that Russia was attempting to “test” Mr Trump with a surge of violence in Ukraine.
Fighting flared this week between Moscow-backed rebels and Ukraine government forces, causing the highest casualty rate since mid-December and cutting off power and water to thousands of civilians.
In a letter to President, Mr McCain wrote: “That this surge of attacks began the day after he talked with you by phone is a clear indication that Vladimir Putin is moving quickly to test you as commander in chief. America's response will have lasting consequences.”
"Vladimir Putin's violent campaign to destabilise and dismember the sovereign nation of Ukraine will not stop unless and until he meets a strong and determined response," he added.
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