Open this photo in gallery: In this photo provided by the Ukrainian Emergency Services on May 8, a rescue worker puts out a fire at a building that was heavily damaged by a Russian strike in Sumy region, Ukraine.Ukrainian Emergency Service/The Associated Press Russia struck northeastern Ukraine on Thursday in the opening hours of a 72-hour ceasefire called by Russian President Vladimir Putin, killing one person, Ukrainian officials said. The unilateral ceasefire coincides with the celebrations in Moscow for the 80th anniversary of victory over Nazi Germany in the Second World War, Russia’s biggest secular holiday. Kyiv has pressed for...