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.
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Emergency services were alerted to the crash at 3.50pm on Thursday, Sussex Police said.
WARNING: Some people may find some of the images in this report distressing.
Medical staff who helped during the Westminster terror attack have received a royal thanks for their life-saving efforts.