Russia's Foreign Minister Sergei Lavrov has called for "urgent measures for preventing an impending humanitarian catastrophe" in Ukraine during a telephone call with US counterpart John Kerry, his department says.
A statement from the Russian Foreign Ministry said Kerry "confirmed such work is being carried out with the Kiev authorities".
The statement follows reports that Ukrainian forces had surrounded the rebel-held city of Donetsk in the east of the country.
More top news
It will be largely dry with some good sunny spells breaking through across many parts today