KIEV, Ukraine - Ukraine lost eight soldiers Wednesday in a dramatic spike in fighting with pro-Russian gunmen that further imperilled a truce Washington’s top European envoy is desperately trying to salvage in Kiev. Separatist rebels also reported the death of two fighters and a civilian in shelling across the eastern industrial heartland of the former Soviet nation that took a decisive tilt toward the West more than a year ago. The resulting crisis has created waves of concern across Europe and sparked the sternest confrontation between Moscow and the West since the Cold War.

The Kremlin denies backing the militias in order to exact revenge for the February 2014 ouster of a Moscow-backed president that was soon followed by Russia’s seizure of Crimea and the onset of one of Europe’s worst conflicts in decades.