US Secretary of State John Kerry warned Russia that it must not intervene in Ukraine under the "pretext of peacekeeping", his department said.
The statement follows Russia's version of the call, in which its Foreign Minister Sergei Lavrov was said to have called for urgent measures to avert a "humanitarian catastrophe" in the east of the country.
More top news
A man accused of stabbing his father to death during a row over food has been arrested by police.
The UK's biggest ambulance service is to become the first in the country to be placed in special measures.
Footage of an armed burglar crawling on the floor of a couple's bedroom while they slept just feet away has been released by police.