"The real toll is likely to be much higher," Liz Throssell, a spokesperson for the U.N. human rights office (OHCHR), told a briefing, adding that 253 of the casualties were in the Donetsk and Lugansk regions in eastern Ukraine.

The U.N. World Food Programme is scaling up activities in Ukraine so that it can support up to 3.1 million people, WFP spokesperson Tomson Phiri said, adding: "Food supplies are running low."

(Reporting by Emma Thomasson; Editing by Paul Carrel)